Answer
a. Q2(median) = 1055.5, Q1 = 703.25, Q3 = 1264, Interquartile range = 560.75
b. Percentile (57) = 1065
c. Percentile rank = 45
Work Step by Step
a.$Q1 = (1\div4)\times20=5th = 699, Q2(median) = (2\div4\times20)th+[(2\div4\times20)+1]th \div2= 10th+11th = (1046+1065)\div2 =1055.5 , Q3 = (3\div4\times20)=15th = 1234$
b. Percentile of 57th = $(57\times20\div100)th = 11th = 1065$
c. Percentile rank of 1046 = $(9 \div 20)\times100 \% = 45 \%$
