NBT NBT Statistics and Probability 4

Question 1

A dataset has values 5, 8, 8, 10, 12, 15, 15, 15, 20. What is the mode?

Accepted Answer

15

Answer

The mode is 15 because it appears three times, more than any other value.

Question 2

If two events A and B are mutually exclusive, which of the following is true?

Accepted Answer

P(A and B) = 0

Answer

Mutually exclusive events cannot occur simultaneously, so P(A and B) = 0.

Question 3

A box contains 4 red, 3 blue, and 5 green marbles. What is the probability of NOT picking a blue marble?

Accepted Answer

9/12

Answer

P(not blue) = (4+5)/12 = 9/12 = 3/4.

Question 4

The interquartile range (IQR) of a dataset is best described as:

Accepted Answer

The difference between the third and first quartiles

Answer

The IQR = Q3 − Q1, representing the spread of the middle 50% of the data.

Question 5

A student scores 72, 85, 90, 68, and 75 on five tests. What is the mean score?

Accepted Answer

78

Answer

Mean = (72+85+90+68+75)/5 = 390/5 = 78.

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