Abstract
Adaptive cluster sampling is particularly helpful whenever the target population is unique, dispersed unevenly, concealed or difficult to find. In the current investigation, under an adaptive cluster sampling approach, we propose a ratio-product-logarithmic type estimator employing a single auxiliary variable for the estimation of finite population variance. The bias and mean square error of the proposed estimator are developed by using simulation as well as real data sets. The study results show that for estimating the finite population variance, the proposed estimator outperforms the competing estimators.
Keywords: Adaptive cluster sampling, auxiliary information, bias, mean square error
1. Introduction
In survey sampling, the auxiliary information is mostly used to improve the accuracy of survey estimates. Adaptive Cluster Sampling (ACS) can especially be helpful when the population of interest is uncommon, irregular, concealed or difficult to find. Assessing the prevalence of a rare disease, monitoring the spread of a rare infectious disease, such as a new strain of influenza, in a community, estimating the population of a rare animal species, such as the snow leopard, in a mountainous region are some examples. Firstly, Thompson [12] proposed the adaptive estimators and later on different statisticians like [2,5,7,8,11,13] and many others have contributed in this direction under different sampling designs. In our study, we reviewed some ACS estimators in simple random sampling such as [3,4,6]. Secondly, we have proposed an estimator in adaptive cluster sampling technique by using a simple random sampling design. Finally, we conclude that our proposed ACS estimator is highly efficient than competent mean estimators.
1.1. Adaptive cluster sampling
Consider a population, . Let and represent the study and the auxiliary variables for the unit, respectively. Let population is partitioned into comprehensive networks and denotes the network having units. The initial sample , where taken from the units that were sampled is used to choose the data set , such that, .
The pre-determined value C is chosen prior to the adaptive cluster sampling method. The spatially adjacent units (designated as North, South, East, West, Northwest, Northeast, Southwest, and Southeast) will be added to the sample and observed whether any of the first chosen sample satisfies or exceeds C, i.e. . The units next to them will be chosen if any of these surrounding units meet this condition C, and so on. A network is a grouping of initially sampled units and nearby units that satisfy the predefined value C. Edge units are those units that are found below the value C. A cluster is made up of a network and its edge components. Any first sampled unit that does not satisfy the requirement is regarded as a network of size one (Table 1).
Table 1.
Sampling unit.
| Northwest | North | Northeast |
|---|---|---|
| West | Sampling Unit | East |
| Southwest | South | Southeast |
In order to better understand the adaptive cluster sampling strategy with the condition of adapt C, i.e. , let a population of size units with 6 networks (denoted as , , , , and ) is taken into consideration in Table 2, where are the non-zero elements of the population. Any of the network will select every element in the network , if it is found in where , according to the network's symmetry assumption. In Table 3, the selection of a sample with a size of 5 quadrates is taken using simple random sampling without replacement (SRSWOR). Asterisks(*) are used to represent the units in the initial sample. In Table 4, the initial units choosen in Table 3 are shown having the selected networks, ' ' represents the first sample unit, selected without replacement and we can say that the initial sample unit fulfills the condition ( ) but it's neighboring units cannot satisfy the condition so it is regarded as a network of size 1. Here ' ', ' ', and ' ' represent the second, third and fifth random initial sample units and underline units represent the final sample units with network of sizes 4, 10 and 4, respectively. Here ' ' represent the fourth initial sample unit as it cannot satisfy the condition so it is regarded as a network of size one.
Table 2.
Population networks with edge units.
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Table 3.
Population including the initial samples.
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Table 4.
Population with neighborhood units and edge units.
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1.2. Estimators in adaptive cluster sampling
Isaki [7], suggested the ratio type variance estimator in ACS having the form:
| (1) |
The bias of is expressed as follows:
| (2) |
where , , and
The MSE of is expressed as follows:
| (3) |
Singh et al. [9], proposed the exponential ratio type variance estimator as:
| (4) |
The bias of is expressed as follows:
| (5) |
The MSE of is expressed as follows:
| (6) |
Yasmeen and Thompson [14], proposed variance estimator using the parameters of an auxiliary variable, which can be defined as:
| (7) |
where α and τ are known constants. The bias of is expressed as follows:
| (8) |
where
The MSE of is expressed as follows:
| (9) |
The parameters, namely coefficient of correlation, coefficient of variation and median of the auxiliary variable are considered for different choices of α and τ to suggest some special cases of the estimator, (See Table 5).
Table 5.
Choices of α and τ.
| j | 1 | 2 | 3 |
|---|---|---|---|
| α | 1 | ρ | |
| τ |
2. Proposed adaptive variance estimator
We propose a ratio-product-logarithmic type estimator for estimating the finite population variance where constant needs to be determined and optimized.
| (10) |
We utilize the relative error terms to obtain the bias and MSE of the proposed estimator as:
Replacing the values of and in Equation (10), we get,
| (11) |
Applying the Taylor series on Equation (11) and leaving out terms that are closer to the second order of approximation, we have,
| (12) |
After applying the expectations on both sides of Equation (12), we get,
| (13) |
where,
Squaring both sides of Equation (12) and then taking expectations yields the expression as:
| (14) |
In order to obtain the optimum value of , taking a partial derivative of Equation (14) with respect to and equating to zero, we get,
| (15) |
Substituting the optimum value of in Equation (14) yields the least MSE of the suggested estimator i.e.
| (16) |
which is equal to the MSE of the regression estimator.
3. Results and conclusions
We evaluated the performance of the proposed estimator in relation to the estimator of [7], the estimator of Ref. [9], and the estimator of Ref. [14]. We performed the simulation experiment and also derived few results from the real data sets.
3.1. Simulation study
Zero-inflated Poisson cluster process is used to create a rarely flock artificial population (X) in the survey area, which is divided into squared units. Under this process, the average number of parents (λ) is chosen to be 5. The initial sample ranges from 45 to 65, with a 400 size of population. Using a linear and exponential model to simulate the values for the study variable (Y ) in order to assess how well the suggested estimator performs:
Model 1 where
Model 2 where
The absolute relative bias (ARB) and the mean square error(MSE) are expressed as:
and
where T is the total number of iterations and is the value of the estimator for the sample. The proposed estimator ( ) is compared with the Equations (1), (4) and (7).
In order to obtain the precise estimates, 1000 iterations have been used to generate the samples from both artificial populations, respectively. The Absolute Relative Bias ( ) and Percent Relative Efficiencies ( ) of all the estimators are computed for different optimum values of , ranging from 0.1 to 0.6.
3.2. Real data
We consider three real data sets for numerical comparisons of the proposed and existing estimators.
Population I: [Source: [10]]
The Blue-winged teal data, shown in Figures 1 and 2 is used to evaluate the performance of the suggested estimator. The data statistics are given in Table 6. Let auxiliary variable (X) represents the number of blue wings and the values of the study variable (Y) are generated by using the statistical Model 1, i.e.
Figure 1.
Blue Wing(X).
Figure 2.
Blue Wing(Y).
Table 6.
Data summary of Population I.
| N = 50 | ||
|---|---|---|
, where Population II: [Source: [1]]
The effectiveness of the suggested estimate is assessed using the annual number of tornadoes in Lafayette Parish, as in Figures 3 and 4, Louisiana, US, from 1950 to 2012. The data statistics are given in Table 7. The number of tornado occurrences in Lafayette Parish is considered as an auxiliary variable (X) and are used to generate the values of study variable (Y ) using the statistical Model 1.
Figure 3.
Number of Tornado occurrences in Lafayette Parish(X).
Figure 4.
Number of Tornado occurrences in Lafayette Parish(Y).
Table 7.
Data summary of Population II.
| N = 63 | ||
|---|---|---|
; where
Population III: [Source: [1]]
The performance of the suggested estimator is assessed using the annual number of large US earthquakes data (those with magnitude at least 7.0) from 1950 to 2012, shown in Figures 5 and 6, respectively. The data statistics are given in Table 8. The number of major US earthquakes is considered as an auxiliary variable (X) and is used to generate the values of study variable (Y) using the statistical Model 1, i.e.
Figure 5.
US earthquake(X).
Figure 6.
US earthquake(Y).
Table 8.
Data summary of Population III.
| N = 63 | ||
|---|---|---|
, where
4. Concluding remarks
The results based on the simulated data are given in Tables 9 – 12. We obtain the percentage relative efficiencies of the proposed estimator with respect to the Equations (1), (4) and (7). Tables 9 and 11, based on T = 1000 iterations show the absolute relative biases of the suggested and the competent estimators for the simulated data. The bias of the suggested estimator decreases as the sample size increases for all cases of . Table 10 based on Model 1 shows the percentage relative efficiencies of the suggested estimator for simulated data. The suggested estimator performs better as compared to all other competent estimators for all cases of , especially suggested estimator is more efficient with a maximum efficiency of 13693.96 for a sample of size 60 when is 0.3. It is observed that by increasing the sample size, the efficiency of the proposed estimator increases for all cases of . Table 12 based on Model 2, shows the percentage relative efficiencies of the suggested estimator for simulated data. The suggested estimator performs better as compared to all other competent estimators for all cases of . Table 13, for Population I, considers the efficiencies of proposed estimator for five different sample sizes. Again it is more efficient than the considered estimators with a maximum efficiency of 744000006714 for a sample of size 30 when is 0.4. Tables 14 and 15 for Population II and Tables 16 and 17 for Population III, consider six different sample sizes for different optimum values of . The suggested estimator is more efficient than the competent estimators (Table 18).
Table 9.
of proposed and competent estimators for varying sample sizes using simulated data (Model 1).
| n | ||||||
|---|---|---|---|---|---|---|
| 45 | 1.087438 | 1.023858 | 1.150881 | 1.141249 | 1.130281 | 1.018675 |
| 50 | 1.078438 | 1.022858 | 1.140881 | 1.140249 | 1.129281 | 1.017875 |
| 55 | 1.072296 | 1.024944 | 1.14689 | 1.146358 | 1.137002 | 1.020477 |
| 60 | 1.050103 | 1.016279 | 1.141234 | 1.14089 | 1.136879 | 1.014521 |
| 65 | 1.051101 | 1.020079 | 1.146705 | 1.146338 | 1.140642 | 1.017943 |
| 45 | 1.091378 | 1.026848 | 1.142017 | 1.141214 | 1.125323 | 1.015585 |
| 50 | 1.080323 | 1.030915 | 1.151883 | 1.151391 | 1.145201 | 1.028551 |
| 55 | 1.056838 | 1.018254 | 1.141948 | 1.141551 | 1.136238 | 1.015948 |
| 60 | 1.05886 | 1.023823 | 1.149337 | 1.148987 | 1.14501 | 1.022845 |
| 65 | 1.049255 | 1.015833 | 1.140963 | 1.140597 | 1.135485 | 1.013732 |
| 45 | 1.086384 | 1.027582 | 1.144586 | 1.14398 | 1.135245 | 1.022805 |
| 50 | 1.070573 | 1.020401 | 1.140331 | 1.139793 | 1.131276 | 1.014294 |
| 55 | 1.074141 | 1.026597 | 1.148587 | 1.148118 | 1.141575 | 1.022922 |
| 60 | 1.061357 | 1.019297 | 1.141924 | 1.141411 | 1.132071 | 1.011213 |
| 65 | 1.055562 | 1.026691 | 1.155015 | 1.154712 | 1.151125 | 1.026486 |
| 45 | 1.086936 | 1.031974 | 1.151202 | 1.150627 | 1.142149 | 1.02674 |
| 50 | 1.073764 | 1.030864 | 1.154252 | 1.153795 | 1.147483 | 1.028375 |
| 55 | 1.070762 | 1.029267 | 1.152978 | 1.152543 | 1.14678 | 1.027676 |
| 60 | 1.053741 | 1.014844 | 1.137748 | 1.137323 | 1.131142 | 1.01146 |
| 65 | 1.048829 | 1.026906 | 1.157493 | 1.157356 | 1.159352 | 1.038837 |
Table 12.
of proposed estimator w.r.t the competent estimators for varying sample sizes using simulated data (Model 2).
| n | |||||
|---|---|---|---|---|---|
| 45 | 851.909 | 127.005 | 808.7862 | 702.5185 | 688.4166 |
| 50 | 871117.6 | 2297.852 | 1655426 | 1435544 | 1428508 |
| 55 | 7259.109 | 249.6935 | 13797.2 | 11856.59 | 11482.97 |
| 60 | 75562.69 | 149.05076 | 257206 | 225131.7 | 220504.3 |
| 65 | 334.5373 | 110.3742 | 554.11 | 515.3116 | 510.7498 |
| 45 | 597.9574 | 111.7698 | 600.1807 | 539.7362 | 537.4432 |
| 50 | 6006.285 | 146.9261 | 3989.288 | 2785.683 | 2348.469 |
| 55 | 218.1572 | 100.1989 | 282.0602 | 266.7877 | 267.1146 |
| 60 | 503.9784 | 112.7732 | 897.5202 | 824.1415 | 816.9617 |
| 65 | 494.437 | 121.7167 | 1028.633 | 941.5646 | 924.8741 |
| 45 | 125.2449 | 228.161 | 332.3994 | 275.0163 | 300.4245 |
| 50 | 634.6963 | 161.9058 | 683.0476 | 599.1843 | 575.211 |
| 55 | 772.2842 | 128.1051 | 1279.93 | 1143.451 | 1122.074 |
| 60 | 187.281 | 163.6964 | 499.1783 | 405.8054 | 388.0088 |
| 65 | 155.9294 | 126.9701 | 822.1409 | 820.0346 | 862.7056 |
| 45 | 17959.69 | 1880.826 | 10054.72 | 7188.266 | 5966.995 |
| 50 | 1376.721 | 187.9024 | 1591.226 | 1378.897 | 1333.06 |
| 55 | 145.713 | 132.9293 | 368.8383 | 363.6415 | 383.6071 |
| 60 | 253.9088 | 198.0452 | 426.5721 | 401.556 | 400.3939 |
| 65 | 2143.953 | 253.1672 | 13389.9 | 12091.99 | 12167.08 |
Table 11.
of proposed and competent estimators for varying sample sizes using simulated data (Model 2).
| n | ||||||
|---|---|---|---|---|---|---|
| 45 | 1.070244 | 1.026508 | 1.068418 | 1.063697 | 1.063044 | 1.023409 |
| 50 | 1.032713 | 1.000732 | 1.045475 | 1.042279 | 1.042172 | 0.9993612 |
| 55 | 1.036956 | 1.006039 | 1.051327 | 1.047508 | 1.046738 | 1.003455 |
| 60 | 1.02481 | 0.9996576 | 1.046619 | 1.043551 | 1.043091 | 0.9980611 |
| 65 | 1.066683 | 1.037877 | 1.086108 | 1.083003 | 1.08263 | 1.036005 |
| 45 | 1.074762 | 1.031755 | 1.074903 | 1.070979 | 1.070826 | 1.029982 |
| 50 | 1.053257 | 1.003797 | 1.043218 | 1.03595 | 1.032927 | 0.9919992 |
| 55 | 1.103181 | 1.069605 | 1.117461 | 1.114209 | 1.11428 | 1.069535 |
| 60 | 1.054078 | 1.025054 | 1.072502 | 1.069433 | 1.069125 | 1.023534 |
| 65 | 1.050136 | 1.024371 | 1.072757 | 1.069566 | 1.068938 | 1.021997 |
| 45 | 1.013487 | 0.9794461 | 1.022602 | 1.020468 | 1.021438 | 0.9860547 |
| 50 | 1.081481 | 1.040658 | 1.084565 | 1.07914 | 1.07752 | 1.031739 |
| 55 | 1.05126 | 1.020284 | 1.066278 | 1.06259 | 1.061993 | 1.017805 |
| 60 | 1.013157 | 0.9869118 | 1.032855 | 1.029525 | 1.028848 | 0.983847 |
| 65 | 1.026192 | 1.010209 | 1.061439 | 1.061359 | 1.062961 | 1.020776 |
| 45 | 1.086279 | 1.027244 | 1.064305 | 1.054217 | 1.049308 | 0.9924873 |
| 50 | 1.060921 | 1.021876 | 1.06557 | 1.06097 | 1.059931 | 1.015688 |
| 55 | 1.042754 | 1.019693 | 1.068612 | 1.06812 | 1.069992 | 1.035247 |
| 60 | 1.071511 | 1.044049 | 1.092986 | 1.090188 | 1.090056 | 1.044506 |
| 65 | 1.015852 | 0.993209 | 1.041115 | 1.039022 | 1.039146 | 0.9953604 |
Table 10.
of proposed estimator w.r.t the competent estimators for varying sample sizes using simulated data (Model 1).
| n | |||||
|---|---|---|---|---|---|
| 45 | 1633.565 | 164.04 | 12045.12 | 11856.067 | 11206.015 |
| 50 | 1771.246 | 159.7656 | 5650.233 | 5600.034 | 4764.053 |
| 55 | 1164.709 | 145.9218 | 4741.679 | 4707.567 | 4128.775 |
| 60 | 1084.086 | 123.9402 | 8397.971 | 8357.406 | 7891.563 |
| 65 | 756.4666 | 123.8281 | 6079.778 | 6049.646 | 5590.907 |
| 45 | 3102.573 | 281.9501 | 7436.458 | 7353.2 | 5801.68 |
| 50 | 757.3076 | 116.6367 | 2676.476 | 2659.248 | 2447.628 |
| 55 | 1164.605 | 129.0634 | 7113.869 | 7074.36 | 6556.909 |
| 60 | 630.2147 | 108.3734 | 3975.075 | 3956.588 | 3749.537 |
| 65 | 1163.667 | 130.5499 | 9285.793 | 9237.95 | 8582.962 |
| 45 | 1347.533 | 144.1588 | 3740.354 | 3709.268 | 3275.774 |
| 50 | 2189.978 | 195.8082 | 8539.204 | 8474.376 | 7480.102 |
| 55 | 986.6557 | 133.0879 | 3910.21 | 3885.739 | 3552.199 |
| 60 | 2606.696 | 276.1642 | 13693.96 | 13595.94 | 11871.04 |
| 65 | 423.463 | 101.4923 | 3221.812 | 3209.305 | 3063.152 |
| 45 | 1004.897 | 141.3002 | 3010.448 | 2987.723 | 2662.961 |
| 50 | 647.7618 | 117.6634 | 2793.214 | 2776.79 | 2554.975 |
| 55 | 626.2469 | 111.4022 | 2883.186 | 2866.917 | 2655.726 |
| 60 | 193.081 | 161.6822 | 12399.73 | 12323.86 | 11247.02 |
| 65 | 156.4515 | 149.06955 | 1582.868 | 1580.131 | 1620.208 |
Table 13.
of proposed estimator w.r.t the competent estimators for varying sample sizes using Population I.
| n | |||||
|---|---|---|---|---|---|
| 18 | 1029.19 | 134.7084 | 105398551 | 105398475 | 104474353 |
| 21 | 1114.727 | 137.7392 | 194513624 | 194513509 | 193058045 |
| 24 | 604.1688 | 106.4814 | 212487821 | 212487740 | 211685102 |
| 27 | 483.2343 | 100.3323 | 309281744 | 309281657 | 308462929 |
| 30 | 1213.376 | 147.9274 | 1390663535 | 1390663119 | 1384449233 |
| 18 | 1149.76 | 133.9964 | 119563611 | 119563451 | 108563341 |
| 21 | 2798.827 | 248.7136 | 501158742 | 501158383 | 495546875 |
| 24 | 609.2466 | 198.07723 | 185858640 | 185858563 | 185113827 |
| 27 | 9988.974 | 750.6189 | 5423054186 | 5423051333 | 5371193833 |
| 30 | 469.038 | 198.3129 | 480609761 | 480609647 | 479359789 |
| 18 | 3068.978 | 273.8398 | 304050080 | 304050567 | 30003672 |
| 21 | 2481.085 | 242.0711 | 391856540 | 391856254 | 387544750 |
| 24 | 1660.4 | 183.0128 | 535495636 | 535495361 | 531520060 |
| 27 | 6461.499 | 556.8218 | 3267849410 | 3267847824 | 3241080769 |
| 30 | 646671.9 | 39235.34 | 744000006714 | 734000003450 | 72900080025 |
| 18 | 491901.4 | 30239.78 | 33559788455 | 33559748480 | 32865165708 |
| 21 | 300735.2 | 16876.52 | 43695781764 | 43695743645 | 43051066401 |
| 24 | 846.1205 | 114.8052 | 271273612 | 271273488 | 269746955 |
| 27 | 201.0811 | 153.31221 | 134023646 | 134023617 | 133953341 |
| 30 | 207.483 | 154.2352 | 221940132 | 221940094 | 221813783 |
| 18 | 5248.737 | 441.0077 | 353338686 | 353338328 | 347937843 |
| 21 | 1201.554 | 154.2412 | 217521561 | 217521427 | 215707126 |
| 24 | 34785.16 | 2806.556 | 8864133305 | 8864127508 | 8767120809 |
| 27 | 2887.813 | 320.2192 | 1792225399 | 1792224665 | 1780907503 |
| 30 | 11198.17 | 742.5287 | 11864175416 | 11864170716 | 11777509382 |
Table 14.
of proposed and competent estimators for varying sample sizes using Population II.
| n | ||||||
|---|---|---|---|---|---|---|
| 15 | 1.014276 | 1.004255 | 1.39575 | 1.395625 | 1.392627 | 1.003362 |
| 18 | 1.009865 | 1.004299 | 1.396943 | 1.396869 | 1.395354 | 1.004277 |
| 21 | 1.005104 | 1.002107 | 1.394668 | 1.394627 | 1.393996 | 1.002431 |
| 24 | 1.005216 | 1.000182 | 1.391854 | 1.391768 | 1.388498 | 0.998234 |
| 27 | 1.001578 | 0.998691 | 1.390318 | 1.390266 | 1.388266 | 0.9975442 |
| 30 | 1.002715 | 1.000459 | 1.392931 | 1.392891 | 1.391373 | 0.9996175 |
| 15 | 1.012521 | 1.004206 | 1.396112 | 1.395997 | 1.393004 | 1.00309 |
| 18 | 1.012545 | 1.007735 | 1.401858 | 1.401796 | 1.400869 | 1.008799 |
| 21 | 1.00515 | 1.001502 | 1.393712 | 1.393659 | 1.392449 | 1.001473 |
| 24 | 1.004182 | 1.000886 | 1.393093 | 1.393041 | 1.391432 | 0.9999469 |
| 27 | 1.003221 | 1.002264 | 1.39553 | 1.395519 | 1.395759 | 1.003473 |
| 30 | 1.00306 | 1.001501 | 1.394481 | 1.394455 | 1.393701 | 1.001138 |
| 15 | 1.011476 | 1.000931 | 1.391054 | 1.390905 | 1.386523 | 0.9972514 |
| 18 | 1.008012 | 1.000987 | 1.392192 | 1.392082 | 1.388561 | 0.9974882 |
| 21 | 1.003828 | 1.000128 | 1.391875 | 1.391819 | 1.390293 | 0.9993271 |
| 24 | 1.005012 | 1.002269 | 1.39513 | 1.395088 | 1.393996 | 1.001896 |
| 27 | 1.004821 | 1.00287 | 1.396207 | 1.396177 | 1.395441 | 1.002818 |
| 30 | 1.003425 | 1.002863 | 1.396471 | 1.396468 | 1.396978 | 1.004985 |
| 15 | 1.018897 | 1.006396 | 1.398533 | 1.398391 | 1.394569 | 1.003344 |
| 18 | 1.009335 | 1.004289 | 1.397108 | 1.39704 | 1.395621 | 1.005052 |
| 21 | 1.004613 | 1.001406 | 1.393689 | 1.393642 | 1.392641 | 1.001931 |
| 24 | 1.003394 | 1.000879 | 1.393202 | 1.393164 | 1.39236 | 1.001299 |
| 27 | 1.003603 | 1.001736 | 1.394635 | 1.394608 | 1.393997 | 1.002017 |
| 30 | 1.001177 | 0.999731 | 1.392023 | 1.392 | 1.3914 | 0.9995492 |
Table 15.
of proposed estimator w.r.t the competent estimators for varying sample sizes using Population II.
| n | |||||
|---|---|---|---|---|---|
| 15 | 1463.435 | 151.5735 | 1052489 | 1051827 | 1035963 |
| 18 | 470.6865 | 100.8845 | 692070.7 | 691813.2 | 686545.6 |
| 21 | 365.5137 | 179.0846 | 1817645 | 1817272 | 1811470 |
| 24 | 2038.407 | 129.00679 | 9605461 | 9601260 | 9441848 |
| 27 | 112.8823 | 171.1129 | 3993175 | 3992112 | 3951354 |
| 30 | 74815.13 | 6656.838 | 1120422354 | 1120192397 | 1111564796 |
| 15 | 1315.564 | 171.8123 | 1220508 | 1219799 | 1201459 |
| 18 | 196.7733 | 178.41684 | 187204.9 | 187147.6 | 186285.8 |
| 21 | 820.3635 | 103.0079 | 3994122 | 3993056 | 3968571 |
| 24 | 10973.34 | 961.9897 | 77552563 | 77531680 | 76899193 |
| 27 | 187.6768 | 148.3856 | 993583.7 | 993532.5 | 994735.7 |
| 30 | 471.9621 | 149.14 | 5811350 | 5810595 | 5788420 |
| 15 | 2836.614 | 40.51732 | 3032097 | 3029788 | 2962327 |
| 18 | 1790.17 | 154.65729 | 3810061 | 3807931 | 3739922 |
| 21 | 62704.62 | 1320.89 | 515292703 | 515146504 | 511146066 |
| 24 | 529.1133 | 133.5036 | 2725967 | 2725391 | 2710370 |
| 27 | 257.0692 | 103.15 | 1429092 | 1428875 | 1423584 |
| 30 | 151.2306 | 137.5962 | 523793.3 | 523785.2 | 525131.7 |
| 15 | 2546.748 | 321.8781 | 1077772 | 1077006 | 1056467 |
| 18 | 313.8093 | 174.40828 | 512930.4 | 512754.8 | 509100.8 |
| 21 | 442.5087 | 161.49963 | 2629928 | 2629305 | 2615958 |
| 24 | 468.5984 | 158.76736 | 4789986 | 4789081 | 4769537 |
| 27 | 265.6398 | 178.89759 | 2463532 | 2463186 | 2455580 |
| 30 | 116095.9 | 2202.422 | 6360257437 | 6359512181 | 6340062701 |
Table 16.
of proposed and competent estimators for varying sample sizes using Population III.
| n | ||||||
|---|---|---|---|---|---|---|
| 15 | 1.020777 | 1.005651 | 1.615267 | 1.615063 | 1.608538 | 1.003461 |
| 18 | 1.013871 | 1.004487 | 1.615202 | 1.615066 | 1.610836 | 1.003316 |
| 21 | 1.006402 | 1.000986 | 1.611009 | 1.610925 | 1.608354 | 1.000394 |
| 24 | 1.007537 | 1.002801 | 1.614238 | 1.614165 | 1.611927 | 1.002261 |
| 27 | 1.004021 | 1.000045 | 1.61022 | 1.610153 | 1.607739 | 0.9993182 |
| 30 | 1.002579 | 0.999695 | 1.610066 | 1.610016 | 1.608177 | 0.9991497 |
| 15 | 1.018776 | 1.004072 | 1.612892 | 1.612689 | 1.606046 | 1.001158 |
| 18 | 1.012162 | 1.005619 | 1.617721 | 1.617637 | 1.616165 | 1.006031 |
| 21 | 1.007382 | 1.002675 | 1.613844 | 1.613779 | 1.612376 | 1.00275 |
| 24 | 1.006166 | 1.00183 | 1.612814 | 1.612746 | 1.610649 | 1.001203 |
| 27 | 1.003502 | 1.001168 | 1.612338 | 1.612308 | 1.612018 | 1.00166 |
| 30 | 1.002408 | 1.000362 | 1.611297 | 1.611266 | 1.610524 | 1.000362 |
| 15 | 1.024372 | 1.005116 | 1.613364 | 1.613105 | 1.604133 | 0.9994165 |
| 18 | 1.010695 | 1.005213 | 1.617429 | 1.617359 | 1.616351 | 1.006284 |
| 21 | 1.008602 | 1.002783 | 1.613793 | 1.613709 | 1.611206 | 1.001903 |
| 24 | 1.005676 | 1.001894 | 1.613001 | 1.612947 | 1.611687 | 1.001969 |
| 27 | 1.004823 | 1.000794 | 1.611472 | 1.611402 | 1.608666 | 0.9990579 |
| 30 | 1.002722 | 1.000517 | 1.611547 | 1.611511 | 1.610458 | 1.000218 |
| 15 | 1.018683 | 1.005987 | 1.616338 | 1.616173 | 1.611731 | 1.004517 |
| 18 | 1.012175 | 1.002729 | 1.612418 | 1.612286 | 1.608257 | 1.000666 |
| 21 | 1.012319 | 1.003225 | 1.613629 | 1.613515 | 1.61013 | 1.001389 |
| 24 | 1.005256 | 1.002047 | 1.613455 | 1.613408 | 1.612427 | 1.00242 |
| 27 | 1.004809 | 1.001709 | 1.61307 | 1.613024 | 1.611782 | 1.001492 |
| 30 | 1.003003 | 1.00206 | 1.614245 | 1.614239 | 1.614905 | 1.003914 |
Table 17.
of proposed estimator w.r.t the competent estimators for varying sample sizes using Population III.
| n | |||||
|---|---|---|---|---|---|
| 15 | 2698.248 | 234.2393 | 2226225 | 2224747 | 2177848 |
| 18 | 1332.65 | 167.49 | 2391752 | 2390690 | 2357961 |
| 21 | 4443.237 | 242.8941 | 33269653 | 33260490 | 32981393 |
| 24 | 785.217 | 140.2564 | 4411303 | 4410258 | 4378212 |
| 27 | 9553431 | 220357.4 | 1620000000 | 1610006700 | 1610000034 |
| 30 | 31233.09 | 387.6709 | 1105631895 | 1105451365 | 1098802199 |
| 15 | 11348.82 | 674.2175 | 11301537 | 11294051 | 11050759 |
| 18 | 366.9017 | 188.0904 | 852499.8 | 852269.3 | 848214.5 |
| 21 | 555.0018 | 195.6383 | 3235443 | 3234759 | 3220009 |
| 24 | 1335.599 | 178.3181 | 10767058 | 10764668 | 10691183 |
| 27 | 321.0665 | 162.2387 | 6942992 | 6942314 | 6935763 |
| 30 | 893.4835 | 100.0415 | 35398278 | 35394695 | 35308941 |
| 15 | 9069669 | 483779.7 | 5454391624 | 5449792234 | 5291614742 |
| 18 | 267.178 | 171.4737 | 790783.3 | 790604.4 | 788027.8 |
| 21 | 1301.462 | 180.2847 | 5719478 | 5717899 | 5671417 |
| 24 | 579.2815 | 194.4422 | 5422651 | 5421691 | 5399462 |
| 27 | 39742.21 | 2811.619 | 494073136 | 493959731 | 489555010 |
| 30 | 1466.738 | 178.9684 | 47869048 | 47863515 | 47698977 |
| 15 | 1393.216 | 164.7335 | 1416613 | 1415856 | 1395537 |
| 18 | 9282.632 | 648.9909 | 21158988 | 21149861 | 20872728 |
| 21 | 3988.824 | 358.204 | 8925899 | 8922602 | 8824513 |
| 24 | 368.1566 | 177.7081 | 3958492 | 3957896 | 3945256 |
| 27 | 643.3703 | 121.1126 | 8081152 | 8079933 | 8047285 |
| 30 | 164.7527 | 135.4246 | 1802228 | 1802190 | 1806096 |
Table 18.
of proposed and competent estimators for varying sample sizes using the Population I.
| n | ||||||
|---|---|---|---|---|---|---|
| 18 | 1.052384 | 1.018633 | 17.92306 | 17.92306 | 17.8487 | 1.015984 |
| 21 | 1.039891 | 1.013698 | 17.87176 | 17.87175 | 17.80851 | 1.011598 |
| 24 | 1.027956 | 1.011446 | 17.87516 | 17.87516 | 17.84326 | 1.011077 |
| 27 | 1.020576 | 1.009103 | 17.86027 | 17.86027 | 17.83794 | 1.009087 |
| 30 | 1.015191 | 1.004979 | 17.79752 | 17.79752 | 17.75995 | 1.004005 |
| 18 | 1.0548 | 1.0185 | 1.021985 | 17.96199 | 17.96198 | 17.9102 |
| 21 | 1.039253 | 1.01135 | 17.82126 | 17.82125 | 17.72681 | 1.007014 |
| 24 | 1.030049 | 1.011757 | 17.87251 | 17.87251 | 17.83867 | 1.011877 |
| 27 | 1.022271 | 1.005742 | 17.77744 | 17.77743 | 17.69702 | 1.001778 |
| 30 | 1.016137 | 1.007117 | 17.8403 | 17.8403 | 17.81839 | 1.007182 |
| 18 | 1.0562 | 1.020834 | 17.90388 | 17.90387 | 17.7867 | 1.0099 |
| 21 | 1.04187 | 1.012735 | 17.83797 | 17.83796 | 17.74507 | 1.008006 |
| 24 | 1.029127 | 1.009336 | 17.82464 | 17.82464 | 17.76207 | 1.006771 |
| 27 | 1.02311 | 1.006431 | 17.7902 | 17.7902 | 17.72129 | 1.002437 |
| 30 | 1.01513 | 1.00335 | 17.76213 | 17.76213 | 17.70409 | 0.9996944 |
| 18 | 1.063837 | 1.015452 | 17.80422 | 17.80421 | 17.6294 | 1.000417 |
| 21 | 1.043499 | 1.009923 | 17.77097 | 17.77097 | 17.64679 | 1.000302 |
| 24 | 1.029257 | 1.010461 | 17.84853 | 17.84853 | 17.80105 | 1.00973 |
| 27 | 1.020182 | 1.010149 | 17.88467 | 17.88467 | 17.88024 | 1.014085 |
| 30 | 1.015799 | 1.007833 | 17.85724 | 17.85723 | 17.85244 | 1.010816 |
| 18 | 1.064515 | 1.018346 | 17.86832 | 17.86831 | 17.7389 | 1.008474 |
| 21 | 1.039156 | 1.013708 | 17.87235 | 17.87235 | 17.80183 | 1.01094 |
| 24 | 1.032779 | 1.008953 | 17.79903 | 17.79902 | 17.70685 | 1.001284 |
| 27 | 1.020831 | 1.006603 | 17.80397 | 17.80397 | 17.75083 | 1.003469 |
| 30 | 1.015789 | 1.003695 | 17.7663 | 17.76629 | 17.70495 | 0.9979607 |
Finally, ACS is a useful technique as an efficient and effective sampling by using the auxiliary information. So the major purpose of this study is to get the precise estimates of finite population variance as compared to other existing estimators. From the results, it is evident that our proposed ratio-product logarithmic type estimator by using the auxiliary variable under ACS shows high relative efficiency than other competent estimators. This work can be extended in stratified adaptive cluster sampling. Similarly, estimation of population total can be worked out in adaptive cluster sampling. This idea can also be extended by using a two-phase sampling scheme.
Acknowledgments
All authors are thankful to the learned referees for their constructive suggestions, which helped to improve the manuscript.
Disclosure statement
No potential conflict of interest was reported by the author(s).
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