Variance, Standard Deviation and Mixed Practice, Quiz

Find the variance of

2, 4, 6, 8, 10

.

A

40

B

8

C

10

D

2\sqrt{2}

The variance of a data set is

8

. What is its standard deviation?

A

4

B

2\sqrt{2}

C

64

D

\sqrt{2}

5

is added to every observation in a data set. What happens to the standard deviation?

A It increases by

25

B It stays the same

C It is multiplied by

5

D It increases by

5

A series has mean

50

and standard deviation

10

. Find its coefficient of variation.

A

500

B

0.2

C

20

D

5

Series A has mean

40

and SD

8

; series B has mean

60

and SD

9

. Which is more consistent?

A A, because its SD is smaller

B B, with CV

15

C Both are equally consistent

D A, with CV

20

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