Question

A rack of sports jackets with the following prices: 78 dollars, 69 dollars, 54 dollars, 95 dollars, 89 dollars, 40 dollars, 85 dollars.
A box plot is a graph that shows how data are distributed by using the median, quartiles, least value, and greatest value.

Connect to Vocabulary
The lower quartile is the median of the lower half of the data.

The upper quartile is the median of the upper half of the data.

1. Consider the prices for sports jackets that Slavik found: $78, $69, $54, $95, $89, $40, $85. Find the median, the lower quartile, and the upper quartile of the prices.

Answer 1

First sort the prices: 40, 54, 69, 78, 85, 89, 95.

- Median (middle value) = 78.
- Lower half (below median): 40, 54, 69 → lower quartile Q1 = median of these = 54.
- Upper half (above median): 85, 89, 95 → upper quartile Q3 = median of these = 89.

So: median = $78, Q1 = $54, Q3 = $89.