# When examining differences between proportions, it is appropriate to use which approach to defining the

1.

When examining differences between proportions, it is appropriate to use which approach to defining the standard error of the sampling distribution?

A) both approaches are appropriate

B) the pooled-variances approach

C) neither approach is appropriate

D) the separate-variances approach

2. 10. A police department is implementing a new initiative in different high crime areas throughout the city—they will be assigning an officer to walk the area for one month. I have been asked to assess whether the strategy was effective in reducing calls for police service. I am interesting in the number of calls for service in a specific location before an officer was assigned to walk the area and after an officer was assigned to walk the area. What type of statistical technique would I use?

A) T-test for independent samples

B) F-test

C) T-test for dependent samples

D) There is no way to make the comparison.

E) Chi-square test of independence

3.

Typically, when using a t-test to compare means, what level of measurement is the independent variable?

A) Ordinal

B) Interval

C) Nominal

D) Ratio

4.

When the samples are relatively large or are evenly divided, the estimates of the standard error using the pooled-variances and separate-variances approaches will be _____.

A) Exactly equal

B) Similar

C) Statistically significant

D) Dissimilar

5.

Why can we use a normal sampling distribution to test hypotheses involving proportions?

A) because the mean and standard deviation are appropriate statistics to use with proportions

B) because as N increases the sampling distribution of a proportion approximates a normal curve

C) because proportions are ratio-level measures

D) all the answers given

6.

I am getting ready to calculate and independent sample t-test. I have assumed homoscedasticity. What am I assuming?

A) That I fail to reject the null hypothesis.

B) That the standard deviations of the two groups are not equal

C) That the standard deviations of the two groups are equal

D) That I reject the null hypothesis.

7.

A two-sample t-test…

A) compares two samples to one another

B) compares a sample to a known population

C) compares apples and oranges

D) compares a sample to an unknown population

8.

I have completed an F-test and rejected the null hypothesis. What does this mean?

A) I can reject the null hypothesis of no difference between two independent means.

B) I can assume homoscedasticity.

C) I cannot assume homoscedasticity.

D) I can use the pooled variance estimate of t.

9.

The null hypothesis for a difference of means test is generally what?

A) that there are no means

B) that the means are the same

C) that the means are not the same

D) none of the choices given

10.

The assumption that population distributions have equal standard deviations is known as what?

A) homoscedasticity

B) multicolinearity

C) discordancy

D) heteroscedasticity

11.

One of the requirements of the two-sample t-test is that the samples examined be what?

A) proportionate

B) independent

C) equal

D) representative

12.

To perform a t-test comparing means, what “minimal” level of measurement must your dependent variable be?

A) Interval

B) Nominal

C) Ratio

D) Ordinal

13.

A “dependent samples T Test” is used for what type of two samples? (Select all that apply)

A) Control and treatment

B) Matched

C) Independent

14.

The pooled-variance approach to calculating the standard error assumes that the population distributions have _____ variances.

A) large

B) small

C) unequal

D) equal