statistic help

Question

I have no Idea what to do with this!!!!!

 

Below are 36 sorted ages of an acting award winner. Find P₉₀ using the method presented in the textbook

24, 26, 32, 33, 34, 35, 37, 37, 38, 39
39, 41, 44, 42, 43, 46, 48, 51, 52, 53
53, 54, 55, 56, 56, 58, 59, 60, 63, 65
68, 70, 72, 75, 76, 79

 

P_{90 =}

Answer 1

9/10 x 36 = 315/10= 31.5 is roughly 3rd from bottom=P10. more precisely (26+32)/2 = 58/2 = 29

P90 = 90th percentile = about 3rd from top, rough estimate =75. more precisely = (75+76)/2 = 75.5

percentiles are like the median, not mean

except when you have an even number, then take the arithmetic average of the two numbers in the middle or where P90 or P10 is