1. What is the probability that X falls below 0.5?
a. 0.5
b. 0.8
c. 0.3
d. 0
e. none of these
2. What is the probability that X lies between 0.7 and 1.3?
a. 0.5
b. 0.8
c. 0.3
d. 0
e. none of these
3. What is the probability that X lies above 0.2?
a. 0.5
b. 0.8
c. 0.3
d. 0
e. none of these
4. What is the probability that X is equal to 0.5?
a. 0.5
b. 0.8
c. 0.3
d. 0
e. none of these
5. Suppose a density curve is de?ned by the function f (x) = 2 for all values between x = 0 to x = 0.5. Find the median of this density curve.
a. 1
b. 0.25
c. 0.5
d. cannot be determined
e. none of these
6. The distribution of raw scores on a chemistry ?nal is approximately normal with mean of about 50 and standard deviation of about 10. What is the probability that a student will have a raw score that is more than 45?
a. 0.7238
b. 0.3085
c. 0.4500
d. 0.6915
e. none of these
7. Consider problem 6 above. Give the interval for the middle 95% of scores.
a. [45, 55]
b. [30, 70]
c. [20, 80]
d. [40, 60]
e. none of these
8. True or False: On a statistics exam, Joe's score was at the 20th percentile and John's score was at the 40th percentile; thus, we can say that John's score was twice Joe's.
a. True
b. False
9. True or False: On the standard normal curve, the 50th percentile corresponds to the mean value of the data set.
a. True
b. False
10. If a sample has a mean of 48 and a standard deviation of 3.2, what is the value in the set that corresponds to a z-score of -1.6?
a. 38.22
b. 42.88
c. 53.12
d. 46.40
e. none of these
11. Find P (-1.2 < Z < 1.9)
a. 0.9713
b. 0.8562
c. 0.8020
d. 0.7659
e. none of these
12. Find c such that P (Z > c) = 0.3859
a. -0.29
b. 0.35
c. -0.35
d. 0.29
e. none of these
13. The sampling distribution of a statistic is
a. The probability that we obtain the statistic in repeated random samples.
b. The mechanism that determines whether randomization was effective.
c. The distribution of values taken by a statistic in all possible samples of the same sample size.
d. The extent to which the sample results differ systematically from the truth.
e. none of these
14. The expected value of the sampling distribution of the sample mean is equal to
a. the standard deviation of the sampling population
b. the mean of the sampling population
c. the median of the sampling population
d. the population size
e. none of these
15. Power companies kill trees growing near their lines to avoid power failures due to falling limbs in storms. Applying a chemical to slow the growth of the trees is cheaper than trimming, but the chemical kills some of the trees. Suppose that one such chemical would kill 15% of sycamore trees. The power company tests the chemical on 200 sycamores. Consider these a SRS from the population of all sycamore trees. What is the probability that no more than 32 trees are killed?
a. 0.0571
b. 0.6540
c. 0.3460
d. 0.1598
e. none of these