Find the Values of the 30th and 90th Percentiles of the Data

To find the values of specific percentiles in a dataset, we first need to sort the data in ascending order. Once the data is sorted, we can apply the percentile formula, which is given by:

P = (n + 1) * (percentile / 100)

Here, P is the position in the ordered dataset, n is the total number of data points, and ‘percentile’ is the desired percentile value.

Let’s break this down step by step. For the 30th percentile:

1. Sort your data set in ascending order.
2. Determine the total number of data points, n.
3. Calculate the position using the formula: P = (n + 1) * (30 / 100).
4. If P is a whole number, the 30th percentile is the value at that position in the sorted data. If P is not a whole number, round it up to the next whole number and find the corresponding value.

Now, to find the 90th percentile, follow the same steps:

1. Using the same sorted data set, calculate the position for the 90th percentile: P = (n + 1) * (90 / 100).
2. Again, if P is a whole number, take the value at that position. If it is not, round it and find the corresponding value.

By using these steps, you can effectively find the 30th and 90th percentiles of any dataset.