Question

For the data shown in the stem-and-leaf plot, what is the effect on the mean and median of adding the value 20 to the data set?
A. The mean is decreased by about 0.1 and the median is decreased by 2.

B. The mean is decreased by about 0.1 and the median is decreased by 3.

C. The mean is decreased by about 0.15 and the median is decreased by 2.

D. The mean is decreased by about 0.15 and the median is decreased by 3.
The graph is in the comments below.

Answer 1

Where's the data?

Answer 2

Here is the link for the graph.
http://static.k12.com/calms_media/media/1417500_1418000/1417693/1/1349366d505f54d9f968044c6fe97ec47facad33/FGA_130917_261016.jpg

Answer 3

We have:

6, 8, 12, 15, 18, 20, 20, 20, 26, 28, 29, 30, 31, 32, 32, 34

Find the mean, add up all the numbers and divide by the amount of numbers there are

Answer 4

Can you do that?

Answer 5

The mean would be 22.5625. Right @iGreen?

Answer 6

Yes, now we add a 20 in the data and compare the two means.

6, 8, 12, 15, 18, 20, 20, 20, 20, 26, 28, 29, 30, 31, 32, 32, 34

Find the mean again

Answer 7

Oh, and find the medians of both of them also

Answer 8

The median would be 20. Right @iGreen?

Answer 9

For the 2nd one yes, what about the 1st?

Answer 10

The 1st median would be 11.28125. Right @iGreen?

Answer 11

No, what are the two numbers in the middle for the 1st one?

Answer 12

Oh How would i figure that out? @iGreen

Answer 13

Just keep eliminating the numbers at the end.

\(\cancel 6, 8, 12, 15, 18, 20, 20, 20, 26, 28, 29, 30, 31, 32, 32, \cancel{34}\)

Answer 14

20 would be the median for the first one. Right @iGreen?

Answer 15

No, the two middle numbers are 20 and 26.

Add 20 + 26 and then divide by 2.

Answer 16

Oh then the answer would be 23. Right @iGreen?

Answer 17

Yep

Answer 18

23 - 20 = 3

Answer 19

So the answer is D..

Answer 20

I g2g now..

Answer 21

Thank you!