a) To find the 39th percentile:
1. Order all the values in the data set from smallest to largest:
2. Multiply 39% by the total number of values:
3. Round the number you get in previous step to the nearest whole number:
4. The data in the 10th position (ordered values) is the 39th percentile.
39th percentile: 26
The 39th percentile is the data value 26
b) To find the 78th percentile:
1. Use the ordered values you get above:
2. Multiply 78% by the total number of values:
3. Round the number you get in previous step to the nearest whole number:
4. The data in the 20th position (ordered values) is the 78th percentile.
78th percentile: 40
The 78th percentile is the data value 40