GRE Probability and Statistics Concepts 3

Question 1

A coin is flipped 3 times. What is the probability of getting exactly two heads?

Accepted Answer

3/8

Answer

There are 3 favorable arrangements (HHT, HTH, THH) out of 8 outcomes, giving 3/8.

Question 2

The standard deviation measures which characteristic of a data set?

Accepted Answer

Spread around the mean

Answer

Standard deviation quantifies how dispersed the values are around the mean.

Question 3

How many distinct ways can 4 different books be arranged on a shelf?

Accepted Answer

24

Answer

The number of arrangements is 4! = 24.

Question 4

If a card is drawn from a standard 52-card deck, what is the probability it is a face card (J, Q, K)?

Accepted Answer

3/13

Answer

There are 12 face cards out of 52, giving 12/52 = 3/13.

Question 5

What is the mode of the data set {2, 4, 4, 6, 6, 6, 9}?

Accepted Answer

6

Answer

The value 6 appears three times, more than any other, so it is the mode.

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