Second Half of Poli 205

Which of the following is a correctly stated null hypothesis? Select one: a. H0: μ= 3 b. H0: x⎯⎯⎯= 3 c. H0 = 3 d. H0: the sample mean is equal to 3

. H0: μ= 3

Imagine that for a population of 40, the mean is 10.25 with a standard deviation of 2.10. What is the population standard error of the mean ()? You answer should be in the form of 0.00.

0.33

You collect data from a sample of 125 people and calculate a mean of 71.34 and a standard deviation of 13.92. What is the value for the standard error of the mean ( )? Your answer should be in the form of 0.00.

1.24

For a chi-square with 6 groups for the row variable and 2 groups for the column variable, the critical value for α = .05 would be equal to ____. Select one: a. 7.81 b. 9.49 c. 11.07 d. 5.99

11.07

A researcher states the following hypotheses: H0: μDemocrats = μRepublicans and H1: μDemocrats ≠ μRepublicans . Assuming she collects data from 9 Democrats and 9 Republicans, what is the appropriate critical value? Select one: a. 2.110 b. 2.101 c. 2.120 d. 1.734

2.210

A study tests the difference between 20 Democrats and 20 Republicans. In this example, the degrees of freedom (df) is equal to: Select one: a. 19 b. 39 c. 18 d. 38

38

For a set of data with the number of groups = 5 and the total N = 300, the degrees of freedom (df) are equal to

4

For a set of data with the number of groups = 5 and the total N = 200, the expected frequency (fe) for each group is equal to ____.

40

For α = .05 and df = 2, the critical value for a chi-square statistic (χ2) would be ____. Answer should be in the form of 0.000.

5.991

For a study that included 4 groups, the critical value for α = .05 would be ____. Your answer should be in the form of 0.000.

7.815

For a chi-square with 5 groups for the row variable and 3 groups for the column variable, the degrees of freedom (df) would be equal to ____. Select one: a. 8 b. 7 c. 2 d. 5

8

If a researcher wants a wider confidence interval, which of the following would be calculated? Select one: a. 99% confidence interval b. 90% confidence interval c. 95% confidence interval d. 85% confidence interval

99% confidence interval

True or False: A researcher found that his statistic was significant at the p < .01 level, indicating it was "more" significant than if the significance level was found to be p < .05. Select one: True False

False

The probability of making a Type II error is ______. Select one: a. None of the choices b. 0.95 c. 0.05 d. 1 - α

None of the choices

The results of the chi-square test of independence found that fear of crime depended on one's satisfaction with police. If the null hypothesis is rejected, which is the most appropriate conclusion that can be made? Select one: a. There is no relationship between people's feelings and their satisfaction with police b. The was a very small effect between the expected and observed frequencies c. The expected frequencies were equal to the observed frequencies d. One's fear of crime is related to whether or not they are satisfied with police

One's fear of crime is related to whether or not they are satisfied with police

What is the relationship between the size of a sample and the width of the confidence interval for the mean? Select one: a. The larger the sample size, the wider the confidence interval for the mean. b. The larger the sample size, the narrower the confidence interval for the mean. c. The size of the sample has no influence on the width of the confidence interval for the mean. d. The smaller the sample size, the narrower the confidence interval for the mean.

The larger the sample size, the narrower the confidence interval for the mean.

Looking at the degrees of freedom (df) tells you something about the size of the sample. Select one: True False

True

The concerns about hypothesis testing are not inherent in hypothesis tests, but rather due to how researchers interpret the results of statistical analyses Select one: True False Feedback

True

A ____ symbol is part of the _____ hypothesis, and implies this hypothesis is ______. Select one: a. <; alternative; one-tailed b. ≠; alternative; directional c. < or >; null; non-directional d. ≠; null; directional

a. <; alternative; one-tailed

A researcher hypothesizes that women are more in favor of gun control than are men. In conducting an analysis to test this hypothesis, how should the null hypothesis be stated? Select one: a. H0: μWomen = μMen b. H0: μ1 = μ2 c. H0: μWomen > μMen d. H0: μD = 0

a. H0: μWomen = μMen

Which of the following statements would be the correct way to state a conclusion regarding a 95% confidence interval? Select one: a. There is a .95 probability that the population mean is between 35,422 and 41,566. b. There is a .05 probability that the population mean is between 35,422 and 41,566. c. There is a .95 probability that the interval of 35,422 to 41,566 contains the population mean. d. There is a .05 probability that the interval of 35,422 to 41,566 contains the population mean.

a. There is a .95 probability that the population mean is between 35,422 and 41,566.

Holding all else constant, as sample size increases, the sampling distribution of the mean ______. Select one: a. becomes more peaked b. becomes skewed c. has greater variability d. becomes flatter

a. becomes more peaked

The sampling distribution of the mean helps us ______. Select one: a. determine the probability of a sample mean (x¯) b. calculate descriptive statistics c. determine whether our variables are normally distributed d. set alpha (α)

a. determine the probability of a sample mean (x¯)

If there is no relationship between two variables, the linear regression equation looks like a _______ line. Select one: a. horizontal b. curved c. vertical d. significant

a. horizontal

The Pearson correlation coefficient (r) assumes the relationship between two variables is ____. Select one: a. linear b. one-tailed c. positive d. negative

a. linear

For a χ2 = 4.05 with 3 groups, the researcher would: Select one: a. not reject the null hypothesis (p > .05) b. reject the null hypothesis (p >.05) c. reject the null hypothesis (p <.05) d. not reject the null hypothesis (p < .05)

a. not reject the null hypothesis (p > .05)

I would calculate a _______ if I wanted to ______ . Select one: a. regression equation; predict one variable from another variable b. correlation coefficient; test nonlinear relationships c. correlation coefficient; compare groups d. regression equation; test the significance between variables

a. regression equation; predict one variable from another variable

Which of the following affects the width of a confidence interval? Select one: a. the desired level of confidence b. whether the population standard deviation is known c. the population mean d. the sample mean

a. the desired level of confidence

An example of a Type I error is when a researcher concludes ________. Select one: a. groups do not differ when they actually do b. groups are the same when they're actually different c. an effect exists when it actually doesn't d. an effect does not exist when it actually does

an effect exists when it actually doesn't

Calculate the 99% confidence interval for a sample of N = 28 with a mean () = 13.64 and standard deviation (s) = 5.52. Select one: a. 99% CI = 13.64 ± 3.81 b. 99% CI = 13.64 ± 2.88 c. 99% CI = 13.64 ± 1.77 d. 99% CI = 13.64 ± 2.13

b. 99% CI = 13.64 ± 2.88

A researcher hypothesizes that Democrats have higher incomes than do Republicans. In conducting an analysis to test this hypothesis, which of the following is the most appropriate way to state the alternative hypothesis? Select one: a. H1: μincome ≠ μincome b. H1: μDemocrats ≠ μRepublicans c. H1: σDemocrats ≠ σRepublicans d. H1: μ1 = μ2

b. H1: μDemocrats ≠ μRepublicans

Which of the following would have the widest confidence interval for the mean? Select one: a. N = 425 b. N = 140 c. N = 200 d. N = 300

b. N = 140

For which of these reasons would you create a scatterplot between two variables? Select one: a. To see if the variables are categorical or continuous b. To get a sense of the strength of the relationship c. To calculate the degrees of freedom d. To see if the group means are the same Feedback

b. To get a sense of the strength of the relationship

A '≠' symbol in the _____ hypothesis implies this hypothesis is ______. Select one: a. alternative; one-tailed b. alternative; non-directional c. null; two-tailed d. null; directional

b. alternative; non-directional

Statistical power is the probability of ________. Select one: a. detecting an effect when it does not exist b. detecting an effect when it exists c. not detecting an effect when it exists d. not detecting an effect when it does not exist

b. detecting an effect when it exists

In conducting the t-test for independent means, if you _____, the two means _____ significantly different from each other. Select one: a. reject the alternative hypothesis; are b. do not reject the null hypothesis; are not c. reject the null hypothesis; are not d. do not reject the null hypothesis; are

b. do not reject the null hypothesis; are not

One way to reduce the probability of making a Type I error is to ________. Select one: a. use a one-tailed test instead of a two-tailed test b. make it harder to reject the null hypothesis c. make it easier to reject the null hypothesis d. make the region of rejection larger

b. make it harder to reject the null hypothesis

The decision to use a directional versus non-directional alternative hypothesis most directly affects _______. Select one: a. the number of degrees of freedom - df b. the critical value(s) used in hypothesis testing c. the sample size - N d. alpha (α)

b. the critical value(s) used in hypothesis testing

You calculate a correlation coefficient (rather than a t-test or Chi-Square) when _________. Select one: a. all of your variables are measured at the nominal or ordinal level of measurement b. the independent and dependent variables are both continuous c. the null hypothesis is that all of the population means are equal to each other d. the independent variable consists of more than two groups

b. the independent and dependent variables are both continuous

A value of -2.01 for the t-statistic necessarily implies that ______. Select one: a. the mean for the first group is greater than the mean of the second group b. the mean for the first group is less than the mean of the second group c. the distribution of scores for the dependent variable is negatively skewed d. the difference between the two means is statistically significant

b. the mean for the first group is less than the mean of the second group

The sampling distribution of the difference helps us determine ________. Select one: a. the modality of a set of data b. the probability of obtaining a particular difference between sample means (xbar 1 - xbar2) c. the probability of obtaining a particular value of the population mean (m) d. whether a set of data is skewed (asymmetric)

b. the probability of obtaining a particular difference between sample means (xbar 1 - xbar2)

When the null hypothesis is rejected, the results of the analysis may be described as ______. Select one: a. "insignificant" b. "nonsignificant" c. "significant" d. "highly significant"

c. "significant"

Which of the following is a correctly stated alternative hypothesis? Select one: a. H1: μ ≠ 3 b. H1: μ < 3 c. H1: μ= 3 d. H0: μ= 3

c. H1: μ= 3

What is the term for a range or interval of values that has a stated probability of containing an unknown population parameter? Select one: a. confidence interval b. interval estimate c. confidence limits d. point estimate

c. confidence limits

In testing the mean of a sample, the sample mean () is transformed into a t-statistic in order to _____. Select one: a. prove our research hypotheses b. determine whether the alternative hypothesis (H1) should be one-tailed or two-tailed c. determine the probability of obtaining the value of the sample mean d. determine the critical values

c. determine the probability of obtaining the value of the sample mean

A researcher has calculated a z-statistic of 1.92. For a two-tailed test with alpha (α) = .05, which of the following is the most appropriate?

c. do not reject the null (p > .05)

In using the chi-square statistic, most if not all of the expected frequencies (fe) should be: Select one: a. greater than 10 b. greater than or equal to 2 c. greater than 5 d. greater than 0

c. greater than 5

The main concern with lowering the probability of making a Type I error is that it _____ Select one: a. requires collecting more data b. decreases the probability of making a Type II error c. increases the probability of making a Type II error d. increases the likelihood of finding effects when they in fact do not exist

c. increases the probability of making a Type II error

If your value of a statistic like the t-test falls in the _____ area of this distribution, you will ____ the null hypothesis ______ because the probability of the statistic is _____. Select one: a. unshaded; reject; low b. unshaded; not reject; low c. shaded; reject; low d. shaded; not reject; high

c. shaded; reject; low

The ______ of a correlation coefficient (r) indicates the ______ of the relationship. Select one: a. sign (+/-); statistical significance b. range; nature (linear or nonlinear) c. sign (+/-); direction d. value; direction

c. sign (+/-); direction

In using the chi-square statistic, none of the expected frequencies (fe) should be equal to ___. Select one: a. 10 b. 1 c. 5 d. 0

d. 0

In testing the difference between two means, which of the following is implied by the alternative hypothesis (H1)? Select one: a. The difference between the two population means is equal to 0. b. The difference between the two sample means is equal to 0. c. The two population means are equal to each other. d. The difference between the two population means is not equal to 0.

d. The difference between the two population means is not equal to 0

The probability of making a Type I error is typically equal to _____. Select one: a. 0.95 b. μ c. β d. α

d. alpha

Why is the term "highly significant" inappropriate to use when interpreting the probability? Select one: a. because p < .001 is less significant than p < .01 b. because p < .001 is 'better' than p < .01 c. because statistical significance is on a continuum d. because statistical significance is a dichotomy

d. because statistical significance is a dichotomy

A Type II error means that a researcher has ________. Select one: a. correctly concluded that an effect does not exist b. falsely concluded that an effect exists c. correctly concluded that an effect exists d. falsely concluded that an effect does not exist

d. falsely concluded that an effect does not exist

One assumption of the chi-square statistic is that each observation in a set of data is ______. Select one: a. interrelated to other observations b. dependent on all other observations c. independent of some observations and dependent on others d. independent of all other observations

d. independent of all other observations

A researcher draws a random sample of 25 people from a population and calculates the mean of their IQs. If she were to repeat this process of drawing samples and calculating means an infinite number of times, the sample means could be used to create _______ Select one: a. critical values b. z-scores c. research hypotheses d. the sampling distribution of the mean

d. the sampling distribution of the mean

Although their formulas are similar, one difference between the z-score (z) and the t-statistic (t) is that a. only the denominator of the z-score formula (not the t-statistic) is a measure of variability b. z-scores evaluate sample means whereas t-statistics evaluate individual scores c. only the numerator of the z-score formula (not the t-statistic) is the difference between means d. the z-score evaluates individual scores whereas the t-statistic evaluates sample means

d. the z-score evaluates individual scores whereas the t-statistic evaluates sample means

There is a 0.95 probability that a confidence interval contains the ______ score for the population. Select one: a. standard deviation b. mean c. variation d. median

mean

For a χ2 = 10.66, df = 3, and α = .05, the researcher would: Select one: a. reject H0 (p < .05) b. reject H0 (p > .05) c. not reject H0 (p > .05) d. not reject H0 (p < .05)

reject H0 (p < .05)

You test the mean of a sample of 19 people and calculate a value of 2.14 for the t-statistic. For a = .05 (two-tailed), which of the following decisions is most appropriate? Select one: a. do not reject null (p > .05) b. accept alternative (p > .05) c. reject null (p > .05) d. reject null (p < .05)

reject null (p < .05)

In testing the difference between two sample means ( ), when there is no difference between the two means, the value of the t-statistic (t) is equal to 0. Select one: True False

true