Table I.

Best-fit curve data for the experimental group (A)

Class	Class interval	Centre of class interval xk0	Deviation from the centre xk = xk0 – xśr	Standardised result z = xk/s	Y value	Number
						Expected fS	Obtained f0	Decision
1	[36-41]	38.5	−40.61	−2.69	0.0107	0.08	1
2	[42-47]	44.5	−34.61	−2.30	0.0283	0.21	–
3	[48-53]	50.5	−28.61	−1.90	0.0656	0.50	1
4	[54-59]	56.5	−22.61	−1.50	0.1295	0.98	–
5	[60-65]	62.5	−16.61	−1.10	0.2178	1.65	1	χ2 = 26.014 > 21.6660.01;9
6	[66-71]	68.5	−10.61	−0.70	0.3122	2.36	2	H 0 rejected
7	[72-77]	74.5	−4.61	−0.31	0.3802	2.88	1
8	[78-83]	80.5	1.39	0.09	0.3973	3.01	3
9	[84-89]	86.5	7.39	0.49	0.3538	2.68	3
10	[90-95]	92.5	13.39	0.89	0.2684	2.03	7