Find the values of the 30th and 90th percentiles of the data.
18, 9, 7, 5, 11, 7, 17, 20, 19, 2, 17, 12, 5, 1, 13, 12, 11, 15, 16, 20
To find the values of the 30th and 90th percentiles of the data, we first need to arrange the data in ascending order:
1, 2, 5, 5, 7, 7, 9, 11, 11, 12, 12, 13, 15, 16, 17, 17, 18, 19, 20, 20
Now, to find the 30th percentile, we need to calculate 30% of the total number of data points:
30% of 20 = 0.3 * 20 = 6
Since the 30th percentile falls between the 6th and 7th data points, we calculate the average of these two values:
(7 + 9) / 2 = 8
Therefore, the 30th percentile is 8.
To find the 90th percentile, we calculate 90% of the total number of data points:
90% of 20 = 0.9 * 20 = 18
Since the 90th percentile falls between the 18th and 19th data points, we calculate the average of these two values:
(18 + 19) / 2 = 18.5
Therefore, the 90th percentile is 18.5.