Question

Using descriptive statistics, you have found out that it takes an average of 40 minutes to complete a mid-term examination in ISDS 361 A. However, you were surprised to see that the median completion time is 55 minutes. This observation means thata. exam completion time is positively skewedb. exam completion time is negatively skewedc. exam completion time resembles the normal distributiond. exam completion time is probably tri-modal

Answer 1

b. exam completion time is negatively skewed

Explanation:

A data distribution is said to be negatively skewed when median value of the distribution is higher than the average value of the distribution.

In this example

• average mid-term completion time is 40 minutes

• median mid-term completion time is 55 minutes.

thus median > mean, so the mid-term completion time is negatively skewed. Negatively skewed distributions are also called left-skewed.