Question

Suppose that you wish to test a claim about a population mean. Which distribution should be used given
that the sample is a simple random sample, σ is not known, n = 15 and the population is normally
distributed?
a. The z-distribution
b. The t-distribution
c. The Chi-Square Distribution
d. The F-distribution

2) A hypothesis in statistics is a claim or a statement about a
a. sample statistic
b. population parameter
c. legitimate inheritance
d. weather conditions
3) A market researcher selects every 40 th student from a group of 500 students. What method is being used
to select the sample?
a. cluster sampling
b. stratified random sampling
c. volunteer sampling
d. systematic sampling

4) Type II error is
a. the mistake of rejecting the null hypothesis when it is false.
b. the mistake of failing to reject the null hypothesis when it is false.
c. the mistake of rejecting the null hypothesis when it is true.
d. the mistake of failing to reject the null hypothesis when it is true.
5) Which of the following values could not represent a correlation coefficient?
a. 1.045
b. 0
c. 0.928
d. - 1

Page 3 of 10
6) Which of the following would be an appropriate null hypothesis?
a. The mean of a population is equal to 100
b. The mean of a sample is equal to 100.
c. The mean of a population is greater than 100.
d. The mean of a sample is less than 100.

7) The width of a confidence interval estimate of the population mean increases when the:
a. level of confidence increases.
b. sample size decreases.
c. value of the population standard deviation increases.
d. all of these choices are true.
8) Assume n 1 = 382 and x 1 = 72, n 2 = 183 and x 2 = 69, calculate the pooled sample proportion .

a. 0.250
b. 0.125
c. 0.175
d. 0.225

9) The effectiveness of a headache medicine is tested by measuring the intensity of a headache in patients
before and after drug treatment. The data consists of before and after measurements for each patient.
Determine whether the samples are independent or dependent or neither.
a. Dependent
b. Independent
c. Neither
d. Not enough information

10) In a perfectly symmetric bell shaped "normal" distribution:
a. The mean equals the median.
b. The mean equals the mode.
c. The median equals the mode.
d. All of these choices are true.

Answer 1

1) Since is unknown we will use b. The t-distribution

2)  A hypothesis in statistics is a claim or a statement about a
b. population parameter

3) A market researcher selects every 40 th student from a group of 500 students. What method is being used
to select the sample?

In systematic sampling we choose every ith sample So
d. systematic sampling

4) Type II error is
b. the mistake of failing to reject the null hypothesis when it is false.

5) Which of the following values could not represent a correlation coefficient?

Value of  correlation coefficient lies between -1 and 1
a. 1.045

6) Which of the following would be an appropriate null hypothesis?

Null hypothesis is a claim about population parameter and it is always equal to
a. The mean of a population is equal to 100

7) The width of a confidence interval estimate of the population mean increases when the:
d. all of these choices are true.

8) Assume n 1 = 382 and x 1 = 72, n 2 = 183 and x 2 = 69, calculate the pooled sample proportion .

a. 0.250

9) The effectiveness of a headache medicine is tested by measuring the intensity of a headache in patients
before and after drug treatment. The data consists of before and after measurements for each patient.
Determine whether the samples are independent or dependent or neither.
a. Dependent

10) In a perfectly symmetric bell-shaped "normal" distribution:
d. All of these choices are true.