Part I: Multiple Choice Questions (1 point for each question, 20 points in total for PART I)

1.

A description of different houses on the market includes the following three variables. Which of these variables is interval variable?

A)

The square footage of the house

B)

The monthly gas bill

C)

The monthly electric bill

D)

All of the above

2.

We have a data set where the observations are college students. One of the variables in the data set is "gender." The values of gender are 1 if the student is male and 2 if the student is female. What type of variable is gender?

A)

Nominal

B)

Ordinal

C)

Interval

D)

None of the above

3.

What are the possible ways of increasing reliability for a measurement?

A)

Use an objective measure

B)

Provide rigorous training to researchers

C)

Employ multiple researchers to measure the same phenomenon

D)

All of the above

4.

Which statement explains the criterion ofcovariationin determining a causal relationship?

A)

If variable A is the cause of variable B, A must precede B in time.

B)

The association between two variables cannot be explained by a third factor.

C)

Changes in variable A lead to changes in variable B.

D)

There should be a theoretical explanation for this causal relationship.

5.

A consumer agency is testing appliances for a series of articles in their magazine. Currently they are working with cooktops and ranges. They have selected 16 of the most commonly used models. Using a series of tests, the agency will estimate the lifetime of these models. A histogram of these (estimated) lifetimes is shown below.

Select the correct description for the shape of the histogram of the estimated lifetimes of these 16 appliances.

A)

Symmetric

B)

Bimodal

C)

Skewed right

D)

Skewed left

6.

The salaries of Major League Baseball players range from several hundred thousand dollars per year to many millions per year. Suppose a histogram is made of all last year's salaries of Major League Baseball players. Which shape would best describe the shape of this histogram?

A)

Skewed to the left

B)

Bell-shaped

C)

Skewed to the right

D)

Symmetric

7.

Which measure of center should be used to report the average if outliers (extreme values) are detected?

A)

The mean

B)

The median

C)

Either the mean or medianthey will be equal in this case.

D)

Neither the mean nor the medianboth will be much lower than the actual average salary.

8.

The table below presents the size of the mayor's staff for all the 212 cities. What is the median size of Major's staff among all the cities?

Size of Mayor's Staff

Number of Cities

5

21

6

39

7

31

8

98

9

12

10

11

A)

6

B)

7

C)

8

D)

9

9.

Which of the following statements regarding a Normal density curve isFALSE?

A)

It is symmetric.

B)

It has a peak centered above its mean.

C)

The quartiles lie 1 standard deviation below and above the mean.

D)

Its shape can be determined by its mean and standard deviation

10.

Many residents of suburban neighborhoods own more than one car but consider one of their cars to be the main family vehicle. The age of these family vehicles can be modeled by a normal distribution with a mean of 2 years and a standard deviation of 6 months. What percentage of family vehicles is between 1 and 3 years old?

A)

This cannot be determined based on the information given.

B)

68%

C)

95%

D)

99.7%

11.

The scores on a university examination are normally distributed with a mean of 62 and a standard deviation of 11. If the bottom 16% of students will fail the course, what is the lowest mark that a student can have and still be awarded a passing grade?

A)

62

B)

73

C)

51

D)

Not enough information

12.

The head of the Westlane Cultural Center wants to get a sense of how quickly pledges from donors arrive at the center. It takes an average of 28 days, with a standard deviation of 7 days (normal distribution), from the time pledges are made until donations are actually received. To better manage cash flow, the director wants to know what the status of pledges looks like by about 42 days. What is the probability that pledges are received within 42 days?

A)

5%

B)

95%

C)

2.5%

D)

97.5%

13.

A sample of sizenis selected at random from a population that has meanand standard deviation. The sample meanwill be determined from the observations in the sample. Which of the following statements about the sample meanis TRUE?

A)

The mean ofdistribution is the same as the population mean, i.e.,.

B)

The standard deviation of(also called standard error) distribution is.

C)

The standard deviation of(also called standard error) decreases as the sample size grows larger.

D)

All of the above are true.

E)

Only A and B are true.

14.

In order to reduce the standard deviation from the sampling distribution of the sample mean, you should ________.

A)

take larger samples

B)

take smaller samples

C)

take medium size samples

D)

None of the above

15.

A state has just changed one of its toll roads from human collection of tolls to machine collection. The idea behind the change was to allow traffic to flow more smoothly through the toll plaza. A random sample of 100 days under the new machine system of toll collections show a mean of 1261 cars passing per hour with a standard deviation of 59. What is the standard error for the sample mean distribution?

A)

59

B)

5.9

C)

0.59

D)

Unknown

16.

Lucia Letter-Carrier, chief analyst for the U.S. Postal Service, will testify before Congress next week on the Service's parcel delivery efforts. She needs to be concerned about a charge that the delivery time is taking longer. Last year records show that parcels mailed from Washington, D.C. to Los Angeles took an average of 3.1 days. To see if there is any change, a sample of 144 packages mailed from Washington to LA are tracked. The sample shows a mean of 3.3 days and a standard deviation of 1.2. What is the 95% confidence interval (confidence limit) for the sample mean?

A)

3.3 0.95 * 1.2

B)

3.3 1.96 * 1.2

C)

3.3 1.96 * 0.1

D)

None of the above

17.

Following the last question, if the researcher wants to reduce the margin of error, what can be done?

A)

Increase sample size

B)

Reduce sample size

C)

Increase confidence level

D)

None of the above

18.

When we state the alternative hypothesis to look for a difference in a parameterin one direction, we are doing a _____.

A)

one-sided test

B)

two-sided test

C)

None of the above

19.

When you are testing sample means with a large sample (n>1,000), under what circumstance would you reject the null hypothesis and accept the alternative hypothesis for a two-tailed test?

A)

When t-score is greater than 1.96

B)

When t-score is lower than 1.96

C)

When the p-value is greater than alpha (0.05)

D)

Either B or C

20.

In hypothesis testing, if we reject the null hypothesis, we can conclude that

A)

The alternative hypothesis is true

B)

The alternative hypothesis is false

C)

There is no Type I error

D)

There is no Type II error