Table 3.

R-AMSTAR total score	Frequency	Percentile
18.00	1	8.3
19.00	1	16.7
20.00	1	25.0
23.00	1	33.3
24.00	1	41.7
26.00	1	50.0
29.00	1	58.3
30.00	1	66.7
33.00	1	75.0
34.00	1	83.3
36.00	2	100.0

Note. Percentiles ≤ 20.75 would fall in the bottom 25th quartile (grade letter “D”); percentile range 20.76–27.50 = lower 50th or letter C; percentile range 27.6–33.75 = upper quartile till 75th, or letter B; percentiles ≥ 33.75 would fall in the top quartile (up to 100th percentile), or letter grade “A.”