Using the mean concept, it is found that the mean difference between the call times and the company's average call time is given by:
- C. 0.4
- The <em>mean </em>of a data-set is given by the <u>sum of all observations in the data-set divided by the number of observations</u>.
In this problem:
- The four observations are the differences between the time of each phone call and the average time.
- They are: {-2.32, -1.55, 4.79, 0.68}
Hence, the mean difference is:
Hence, option C is correct.
To learn more about the mean concept, you can take a look at brainly.com/question/13451786