Question

Based on data from WHO, a representative sample of 15-year-old males could consist of the following 15 values. Calculate the 85th percentile for weight status.

Answer 1

To calculate the 85th percentile, sort the data, find the index by multiplying 0.85 by the number of data points, then locate the value at this index in the ordered set. If the calculated index is a whole number, average the values at this index and the next. Specific data is needed for the exact calculation.

Step-by-step explanation:

The question asks to calculate the 85th percentile for weight status within a representative sample of 15-year-old males, however, the specific data set required to calculate this is not provided in the question thus an exact value cannot be determined.

For generally calculating the 85th percentile, the steps are as follows:

1. Order the data points from smallest to largest.
2. Determine the index by multiplying the percentile (in decimal form) by the number of data points. Finding the 85th percentile would be 0.85 multiplied by the number of data points.
3. If the index is not a whole number, round up to the nearest whole number, and that gives the position of the percentile in the ordered data set.
4. If the index is a whole number, the percentile is the average of the values at that index and the next highest index in the ordered data set.

In a scenario where normally distributed data like weights of children or the amount of weight lost is concerned, percentiles can also be calculated using z-scores with standard normal distribution tables or statistical software by inputting the mean and standard deviation.