Exercise 22 Page 717

Percentiles separate data sets into 100 equal parts. The percentile rank of a data value is the percentage of data values that are less than or equal to that value. Let's find the percentile rank of a data value 34. Therefore, we have to find how many of the values are less than or equal to 34. Data set 1, 1, 1, 1, 1, 1, 2, 3, 5, 8, 13 21, 34, 55, 89, 89, 89, 89, 89, 89 Now we know that 13 values out of the 20 total values are less than or equal to 34. 13/20 = 0.65 = 65 % The percentile rank of a score of 34 is 65.