Question 1

In writing the results of the t-test in standard APA format, the letters "n.s." imply ______.
A) p < .05
B) p < .01
C) p > .05
D) the null hypothesis was rejected

Accepted Answer

"n.s." stands for "not significant," which means that the p-value was greater than .05 and the results were not statistically significant. Therefore, the correct choice is C, which corresponds to a p-value greater than .05.

Question 2

According to the textbook, what is the difference between the terms "nonsignificant" and "insignificant"?
A) "Insignificant" is not a statistical concept.
B) You use the term "insignificant" when you make the decision to reject the null hypothesis.
C) "Insignificant" implies p < .05; "nonsignificant" implies p < .01.
D) There is no difference between the two concepts-they mean the same thing.

Accepted Answer

According to the textbook, "insignificant" is not a statistical concept, whereas "nonsignificant" is a statistical term used to describe results that do not reach a predetermined level of statistical significance (typically p < .05 or p < .01).

Question 3

According to the textbook, what is the difference between the terms "nonsignificant" and "insignificant"?
A) "Nonsignificant" is less precise than "insignificant."
B) "Nonsignificant" is a statistical concept; "insignificant" is a value judgment.
C) "Nonsignificant" refers to α = .05; "insignificant" refers to α = .01.
D) "Insignificant" is a statistical concept; "nonsignificant" is a value judgment.

Accepted Answer

According to the textbook, "nonsignificant" is a statistical concept that refers to a result that does not meet the criteria for statistical significance, whereas "insignificant" is a value judgment that implies lack of importance or relevance. Therefore, B is the best choice since it accurately captures the difference between the two terms.

Question 4

Which type of statistic would be appropriate for analyzing a within-subjects research design?
A) z-test for one mean
B) t-test for independent means
C) t-test for dependent means
D) t-test for one mean

Accepted Answer

A within-subjects research design involves measuring the same group of participants multiple times under different conditions. Since the same individuals are being measured twice or more, it is important to use a dependent (or paired) samples test to account for individual differences. The appropriate statistic for this kind of design is a t-test for dependent means.

Question 5

For a study analyzing the difference between test scores before and after a treatment was applied, which statistic would be most appropriate for this study?
A) z-test for one mean
B) t-test for one mean
C) t-test for independent means
D) t-test for dependent means

Accepted Answer

A t-test for dependent means, also known as a paired-sample t-test, is appropriate for analyzing the difference between test scores before and after a treatment because it specifically compares the means of two related samples (in this case, the same individuals' scores before and after the treatment). Other options, such as a z-test for one mean or a t-test for independent means, are not appropriate as they do not take the relationship between the two sets of scores into account.

Question 6

A researcher asks 10 people to take sips out of two cups of soda (one with Coke and the other Pepsi) and rate the flavor of both sodas. In analyzing this data, how should the null hypothesis be stated? A) H₀: µ_D = 0 B) H₀: Coke > Pepsi C) H₀: Coke = Pepsi D) H₀: µ₁ = µ₂

Accepted Answer

The null hypothesis in an experiment comparing two groups typically states that there is no difference between the groups. In this case, the correct statement of the null hypothesis would be that the mean rating difference between the two sodas is zero, indicating no preference between Coke and Pepsi, which is represented by the mathematical notation in choice A.

Question 7

A study compares 5 Democrats and 5 Republicans and obtains a value of 2.27 for the t-statistic. For α = .05 (two-tailed), which of the following is the correct way to present this analysis? A) t(10) = 2.27, p > .05 B) t(8) = 2.27, p < .05 C) t(9) = 2.27, p < .05 D) t(8) = 2.27, p > .05

Accepted Answer

The answer of A study compares 5 Democrats and 5...

Question 8

A researcher asks 10 people to take a bite of two different cheese pizzas (Dominos and Round Table) and rate the flavor of both pizzas. In analyzing this data, how should the null hypothesis be stated? A) µ_D = 0 B) µ_D ≠ 0 C) Dominos = Round Table D) µ₁ = µ₂

Accepted Answer

The null hypothesis in experiments comparing two groups typically states that there is no difference between the groups. In this case, it would mean stating that there is no difference in flavor ratings between the Dominos and Round Table pizzas. Choice A, despite its complex notation, is the only option that implies equality (i.e., a difference of 0), which aligns with the concept of a null hypothesis stating no difference.

Question 9

If a researcher has developed a research design in which each participant appears in all levels or categories, this would be considered which type of research design?
A) within-subjects design
B) t-test for independent means
C) between-subjects design
D) t-test for one mean

Accepted Answer

A research design in which each participant appears in all levels or categories is considered a within-subjects design.

Question 10

A ______ is a research design in which each participant appears in all levels or categories of the independent variable.
A) t-test for independent means
B) t-test for one mean
C) between subjects research design
D) within-subjects research design

Accepted Answer

Within-subjects research design, also known as a repeated measures design, involves the same participants being measured multiple times under different conditions or levels of the independent variable. This allows for comparisons within each participant, increasing the statistical power and reducing the error variance.

Question 11

In testing the difference between two sample means, you would examine the ______ of the two groups to test the assumption of homogeneity of variance.
A) standard deviations
B) t-tests
C) means
D) sample sizes

Accepted Answer

To test the assumption of homogeneity of variance, we need to examine the standard deviations of the two groups. Homogeneity of variance means that the groups being compared have approximately equal variances. If the variances of the two groups are not equal, it may affect the results of statistical tests used to compare the means of the two groups.

Question 12

When the null hypothesis is ______, this typically means the research hypothesis is ______.
A) not rejected; supported
B) rejected; supported
C) rejected; not supported
D) rejected; proven

Accepted Answer

When the null hypothesis is rejected, it typically means there is sufficient evidence to support the research hypothesis. Rejecting the null hypothesis suggests that the observed data are inconsistent with the assumption of no effect or no difference, thus supporting the alternative or research hypothesis.

Question 13

The assumption of normality is primarily concerned with ______.
A) the difference between two sample means
B) the shape of the distribution of the dependent variable
C) how samples are drawn from populations
D) the difference between a sample mean and a population mean

Accepted Answer

The assumption of normality is an assumption about the shape of the distribution of the dependent variable, which is typically assessed using measures such as skewness and kurtosis. It is important because many statistical analyses, such as t-tests and ANOVA, assume the data are normally distributed. Therefore, violation of the assumption of normality can lead to inaccurate conclusions.

Question 14

In reporting the results of a statistical analysis in standard APA format, the letters "n.s." mean ______.
A) "nonsignificant"
B) "not sure"
C) "non-statistical"
D) "not standard"

Accepted Answer

"n.s." is commonly used to indicate a non-significant result (i.e., one that did not reach statistical significance).

Question 15

The within-subjects research design tests differences ______.
A) between different groups of participants
B) within the same participant
C) between different groups of participants and within the same participants
D) between a sample mean and a hypothesized population mean

Accepted Answer

The within-subjects research design tests differences within the same participant. It looks at how a participant's behavior or response changes based on different levels or treatments. It does not compare different groups of participants or compare a sample mean to a hypothesized population mean.

Question 16

When the null hypothesis is ______, this typically means the research hypothesis is ______.
A) not rejected; not supported
B) rejected; supported
C) rejected; not supported
D) rejected; proven

Accepted Answer

When the null hypothesis is not rejected, it means that there is not enough evidence to reject it, but it does not necessarily mean that the research hypothesis is proven. Therefore, the research hypothesis is simply not supported.

Question 17

A researcher asks 20 people to take a sip of two different colas (first Coke and then Pepsi) and rate the flavor of both. In analyzing this data, how should the null hypothesis be stated? A) H₀: µ_D ≠ 0 B) H₀: µ_D = 20 C) H₀: Coke = Pepsi D) H₀: µ_D = 0

Accepted Answer

The null hypothesis in this scenario should state that there is no difference in the flavor ratings between Coke and Pepsi, which is represented by stating the mean difference (µ) equals 0.

Question 18

Which of the following would be the most informative way to report the results of a t-test?
A) The mean number of crimes for juveniles in the poverty group (M = 2.45) is significantly higher than the mean number of crimes for juveniles in the non-poverty group (M = .95), t(40) = 3.41, p < .01.
B) The mean number of crimes for juveniles in the poverty group (M = 2.45) is significantly higher than the mean number of crimes for juveniles in the non-poverty group (M = .95).
C) The mean number of crimes for juveniles in the poverty group (M = 2.45) is significantly different than the mean number of crimes for juveniles in the non-poverty group (M = .95), t(40) = 3.41, p < .01.
D) The mean number of crimes for juveniles in the poverty group is significantly higher than the mean number of crimes for juveniles in the non-poverty group, t(40) = 3.41, p < .01.

Accepted Answer

Option A provides the most information as it includes the means of both groups, the t-value, degrees of freedom and p-value. It also specifies the direction of the difference, stating that the mean number of crimes for juveniles in poverty group is significantly higher than the mean number of crimes for juveniles in the non-poverty group.

Question 19

A study compares 6 full-time students and 6 part-time students and obtains a value of 2.31 for the t-statistic. For α = .05 (two-tailed), which of the following is the correct way to present this analysis?
A) t(5) = 2.31, p > .05
B) t(6) = 2.31, p < .05
C) t(10) = 2.31, p < .05
D) t(12) = 2.31, p < .01

Accepted Answer

Since there were a total of 12 participants in the study (6 full-time + 6 part-time), the correct degrees of freedom for the t-test is 10 (12-2). The p-value is less than .05, indicating that the results are statistically significant. However, we cannot determine if the difference is significant in both directions (two-tailed) or only in one direction (one-tailed) based on the information given.

Question 20

In reporting a statistical analysis, a researcher writes "p > .05". By definition this implies that ______.
A) the null hypothesis was rejected
B) p < .01
C) the statistic was in the region of rejection
D) the means of the groups are not different from each other

Accepted Answer

When p > .05, it means that the result is not statistically significant and there is insufficient evidence to reject the null hypothesis. This implies that there is no significant difference between the means of the groups being compared.

Quiz 9: Testing the Difference Between Two Means

In writing the results of the t-test in standard APA format, the letters "n.s." imply ______.

According to the textbook, what is the difference between the terms "nonsignificant" and "insignificant"?

According to the textbook, what is the difference between the terms "nonsignificant" and "insignificant"?

Which type of statistic would be appropriate for analyzing a within-subjects research design?

For a study analyzing the difference between test scores before and after a treatment was applied, which statistic would be most appropriate for this study?

A researcher asks 10 people to take sips out of two cups of soda (one with Coke and the other Pepsi) and rate the flavor of both sodas. In analyzing this data, how should the null hypothesis be stated?

A study compares 5 Democrats and 5 Republicans and obtains a value of 2.27 for the t-statistic. For α = .05 (two-tailed) , which of the following is the correct way to present this analysis?

A researcher asks 10 people to take a bite of two different cheese pizzas (Dominos and Round Table) and rate the flavor of both pizzas. In analyzing this data, how should the null hypothesis be stated?

If a researcher has developed a research design in which each participant appears in all levels or categories, this would be considered which type of research design?

A ______ is a research design in which each participant appears in all levels or categories of the independent variable.

In testing the difference between two sample means, you would examine the ______ of the two groups to test the assumption of homogeneity of variance.

When the null hypothesis is , this typically means the research hypothesis is .

The assumption of normality is primarily concerned with ______.

In reporting the results of a statistical analysis in standard APA format, the letters "n.s." mean ______.

The within-subjects research design tests differences ______.

When the null hypothesis is , this typically means the research hypothesis is .

A researcher asks 20 people to take a sip of two different colas (first Coke and then Pepsi) and rate the flavor of both. In analyzing this data, how should the null hypothesis be stated?

Which of the following would be the most informative way to report the results of a t-test?

A study compares 6 full-time students and 6 part-time students and obtains a value of 2.31 for the t-statistic. For α = .05 (two-tailed) , which of the following is the correct way to present this analysis?

In reporting a statistical analysis, a researcher writes "p > .05". By definition this implies that ______.