Question

When the outliers are removed, how does the mean change?

Answer 1

The mean decreases by 2.75.

The mean increases by 2.75.

The mean increases by 3.25.

There are no outliers

Answer 2

@kropot72

Answer 3

Last time I answered a question like this I got it wrong

Answer 4

can someone explain to me how to do this step by step?

Answer 5

First you need to add the 9 data values:
\[18+(2\times38)+40+(3\times44)+46+48=You\ can\ calculate\]
When you have the total, divide it by 9 to find the mean.
Please post you result, then we can go to the next step.

Answer 6

360/9= 40

Answer 7

Good work! Can you identify any outliers?

Answer 8

50 and 16?

Answer 9

16 is an outlier. Can you see that there is no data value 50 in the diagram?

Answer 10

yes but I cant see data value on 16 and 50 only on 18, 38, 40, 44, 46 and 48

Answer 11

Sorry, my bad. I meant to write that 18 is an outlier. Please don't mistake the numbers on the axis of the diagram for data values.
To find the mean of the data with the outlier 18 removed from the original 9 values, subtract 18 from the previous total of 9 values (360). Then divide the new total by the new number of data values, 8.
\[mean\ without\ outlier=\frac{360-18}{8}=you\ can\ calculate.\]
When you have the value of the new mean, compare it with the mean you found when the outlier was included.

Answer 12

with the original mean divided by 9 or 8?

Answer 13

The original number i got is 40 and the one after is 42.7500

Answer 14

The original mean, with the outlier included in the calculation, has to be divided by the actual number of data values which is 9. There is no way you can calculate a mean correctly unless you divide the sum of the data values by the number of data values.
Note that there are only 8 data values when the outlier is removed. So we get a new total for the sum of the 8 values, and we divide this sum by 8 to find the new mean. It is incorrect to change the original mean with the outlier included by dividing by number of data values that is not 9.

Answer 15

so what do i do with 42.7500 from there?

Answer 16

when I divide 40 by 9 I get 4.4444 and when I divde 42.7500 by 8 I get 5.3438

Answer 17

By removing the outlier from the original data set the mean has increased by:
42.75 - 40.00 = ?
Can you choose the correct answer now?

Answer 18

thank you again your the smartest person to answer my questions ima give the medal now i got2.7500

Answer 19

You're welcome. the correct choice is B.

Answer 20

@kropot72 last question can the outlier be 48 aswell as 18?

Answer 21

An outlier is a data point whose value is well away from other data points. 48 is not well away from the other data points, so 48 is not an outlier.

Answer 22

ahh ok thank you

Answer 23

You're welcome :)