# Questions about probability and statistics

1) Empirical probabilities are:

A) based on the normal curve

B) deeply rooted in probability

C) scores from a sample

D) essentially percentages based on a large number of observations

2) Roughly _________________ percent of the total area under the normal curve rests between the mean and one standard deviation above.

3) Which of the following is true probabilities?

A) a probability varies from 0 to 1.0

B) a 0 probability implies something is possible

C) a 1.0 probability implies something is impossible

D) none of the above

4) The probability of drawing a "four" from a standard deck of 52 cards is:

A) .13

B) .077

C) .019

D) .19

5) The normal curve is:

A) positively skewed

B) applicable to all real life research situations

C) a theoretical idea

D) all the above

6) The probability of you correctly guessing the answer to this question is:

A) .20

B) .50

C) .25

D) .30

7) A number whose Z-score is equal to zero is equal to the mean

A) true

B) false

8) A Z-score tells nothing about the distance of a score from a mean

a) true

b) false

Questions 9-10 refer to the fallowing. Suppose that 43% of inmates in state prisons have psychiatric illness. What is the probability of that:

9) a particular prisoner does not suffer from a psychiatric illness

10) five prisoners do not suffer from a psychiatric illness

Questions 11-15 refer to the following: Suppose that you purchase a lottery ticket that contains four members and a letter such as: 9 7 3 6 Q

11) What is the probability that you match the second digit?

12) What is the probability that you match the first digit?

13) What is the probability that you do not match the third digit?

14) What is the probability that you match the firs, second, and third digits?

15) What is the probability that you match the letter?

16) The average snowfall in Ottawa, Canada in 98 inches per year, with a standard deviation of 25 inches. The average snowfall in Boston, Massachusetts is 44 inches, with a standard deviation of 17 inches. In 1997, Ottawa received 119 inches of snowfall, while Boston recorded 62 inches. Assuming both distributions are normal, calculate using the Table of Proportions of Area under the Normal Curve.

A) Which city had the worse winter of 1997 (relative to its norm)?

B) The percentile rank of Ottawa's 1997 snowfall.

C) The percentile rank of Boston's 1997 snowfall

D) If Boston's 1996 snowfall was 33 inches, what percentage greater was the snowfall of the winter of 1997?

E) A Z-score is a specific case's distance from the mean in __________ units?

17) Drawing one card at random from a standard deck of 52 cars, what is the probability of drawing a joker?

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