Question

The hourly wages earned by 20 employees are shown in the first box-and-whisker plot below. The person earning $15 per hour quits and is replaced with a person earning $8 per hour. The graph of the resulting salaries is shown in plot 2. A box-and-whisker plot is shown. The number line goes from 7 to 15. The whiskers range from 8 to 15, and the box ranges from 8.8 to 10.2. A line divides the box at 9.5. Plot 1 A box-and-whisker plot is shown. The number line goes from 7 to 15. The whiskers range from 8 to 11, and the box ranges from 8.7 to 10. A line divides the box at 9.6. Plot 2 How does the mean and median change from plot 1 to plot 2? The mean and median remain the same. The mean decreases, and the median remains the same. The mean remains the same, and the median decreases. The mean and median decrease.

Answer 1

Answer:

The mean decreases, and the median remains the same.

Step-by-step explanation:

Remember that a box plot is made by the quartiles of the distribution, the maximum value and the minimum value. So, from a box plot we can deduct the range, the median and the interquartile range.

In this case, the median remains the same at $9.5 per hour. The median is indicated by the middle line of the box, and you can observe that it doesn't change.

Now, the range of the data set decreases from 7 to 3.

On the other hand, the mean must decrease, because data greater than $11 doesn't exist in the box plot number 2, and the mean is a central measure sensible to those changes.

Therefore, the right answer is The mean decreases, and the median remains the same.