EC Quiz Questions - Exam 2

Question 1

Imagine that you flip a fair coin five times in a row. If an outcome is a sequence of heads and tails (e.g., HHHTH), how many outcomes are there in the sample space?

Answer 1

32

Question 2

Imagine that you roll a fair, six-sided die three times in a row. Let the variable Y be the sum of the dots on each roll (e.g., for a sequence of 2, 6, 1, X = 9). In the probability distribution for Y, how many possible values of Y are there?

A. Infinitely many
B. 18
C. 216
D. 3
E. 16

Answer 2

C. 16

Question 3

In the U.S., more men smoke cigarettes than smoke cigars. Some men do both. Which of the following statements is therefore true for men in the U.S.?
A. P(smoke cigarettes | smoke cigars) > P(smoke cigars | smoke cigarettes)
B. P(smoke cigarettes | smoke cigars) < P(smoke cigars | smoke cigarettes)
C. P(smoke cigarettes | smoke cigars) = P(smoke cigars | smoke cigarettes)

Answer 3

P(smoke cigarettes | smoke cigars) > P(smoke cigars | smoke cigarettes).

Question 4

What statistic(s) that you can calculate from a sample have a sampling distribution?

Answer 4

Any sample statistic you can calculate

Question 5

Which of the following is/are NOT a test of whether events A and B are independent? Choose ALL THAT APPLY.

A. Assessing whether P(A or B) = P(A) + P(B)
B. Assessing whether P(B|A) = P(B)
C. Assessing whether P(A and B) = P(A) x P(B)
D. Assessing whether P(A|B) = P(B|A)
E. Assessing whether P(A|B) = P(A)

Answer 5

A. Assessing whether P(A or B) = P(A) + P(B)
D. Assessing whether P(A|B) = P(B|A)

Question 6

T or F

If the population distribution is not normal, the sampling distrubtion of the mean becomes more normal as the sample size increases.

Answer 6

T

Question 7

T or F
The sampling distribution of the mean gets skinner as the sample size increases.

Answer 7

T

Question 8

T or F

Even if the population distribution is normal, the sample size needs to be at least 30 before the sampling distribution of the mean is roughly normal.

Answer 8

F

Question 9

T or F

The chance of observing a sample mean that is more than X units away from the population mean is less than the chance of observing and individual score that is more than X units away from the population mean.

Answer 9

T

Question 10

T or F

All else being equal, in order to reduce the width of a 95% CI by a factor of 3, the sample size has to be 9 times larger.

Answer 10

T

Question 11

T or F

For any given sample, the 99% CI for the mean is narrower than the 95% CI for the mean.

Answer 11

F

Question 12

T or F
For any given sample, the 95% CI for the mean has a 95% chance of including x-bar.

Answer 12

F

Question 13

T or F
The variance of the population distribution has no effect on width of a CI for the mean.

Answer 13

F

Question 14

If a population has a mean of 1000 and standard deviation of 200, what is the standard error of the mean for samples of size 100?

A. 20
B. 100
C. 200
D. 10
E. 14.14

Answer 14

A. 20

Question 15

Being a paramedic can be stressful. A researcher wants to test whether, on average, paramedics have blood pressure that is higher than that for the typical adult in the US. She conducts a study in which she records the systolic blood pressure (the first number in a blood pressure reading) of random sample of 136 paramedics. For adults in the US, the mean systolic blood pressure is 128.4, with a standard deviation of 19.6. You can take these values as population parameters. What are the researcher’s null and alternative hypotheses?

A. H(0): mu ≥ 128.4, H(a): mu < 128.4
B. H(0): mu ≤ 128.4, H(a): mu > 128.4
C. H(0): mu = 128.4, H(a): mu ≠ 128.4

Answer 15

B. H(0): mu ≤ 128.4, H(a): mu > 128.4