Q. 21 - The Practice of Statistics for AP

Question

 A large company is interested in improving the efficiency of its customer service and decides to examine the length of the business phone calls made to clients by its sales staff. A cumulative relative frequency graph is shown below from data collected over the past year. According to the graph, the shortest $80\%$of calls will take how long to complete?

(a) Less than $10$ minutes.
(b) At least $10$ minutes.
(c) Exactly $10$ minutes.
(d) At least $5.5$ minutes.
(e) Less than $5.5$minutes.

Step-by-Step Solution

Answer

The shortest of $80\%$ of cell takes less than$10$ minutes. So, the option (a) is correct.

Step 1: Given information

A cumulative relative frequency graph is shown below from data collected over the past year.

Step 2: Explanation

In the graph, minutes are measured on horizontal axis and percent on vertical axis. A line is drawn that touches the blue curve joining to vertical axis and horizontal axis is shown below:

From the graph, concluded that the shortest $80\%$ of the calls are less than $10$ minutes.
Hence, the correct option is (a).