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Sub 505 Level|   Statistics and Sets Problems|                        
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Bunuel
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Hi,

Difficulty level: 600

When a constant term is added to all values in the series, mean and median change by same value. In this case, both will increase by 5.
The standard deviation doesn't change.

Thus, Answer is (D)

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If we add or subtract a constant from all the terms in a series, then the mean and median will change by the value of constant. The deviation remains the same.

Hence, D

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Great Question.
Here
New mean = Old mean +5
New median = Old median +5

New standard deviation = Old standard deviation
Standard deviation just shows the average distance of individual data elements with respect to the mean. Hence it wont change.


Hence D
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Bunuel
A researcher computed the mean, the median, and the standard deviation for a set of performance scores. If 5 were to be added to each score, which of these three statistics would change?

(A) The mean only
(B) The median only
(C) The standard deviation only
(D) The mean and the median
(E) The mean and the standard deviation

If a single value is added with all the values of a set then the standard deviation doesn't change.

Let's check the mean and median with real values:

1,2 and 3 are the values; average\(=\frac{1+2+3}{3}=2\)

The Median\(=2\)

After adding \(5=6+7+8=\frac{21}{3}=7\)

The median\(=7\)

So, Mean and Median are changing.

The answer is \(D\)
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­Same deal as this:

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Hello from the GMAT Club BumpBot!

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