### Independent Samples, Research Design, Repeated-Measures Research Design, Final Test

The key terms in these Statistic chapters include Alpha Level, Critical Region, Type I Error, Research Design, Repeated-Measures Study, Sample, Null Hypothesis, Population, Reject the Null Hypothesis, Variance, Repeated-Measures Research Design, Independent Samples, Z-Score, Distribution, Population Mean, T-Test.

What is the relationship between the alpha level, the size of the critical region, and the risk of a Type I error?

**As the alpha level increases, the size of the critical region increases, and the risk of a Type I error increases.**

Which of the following research situations would be most likely to use a between-subjects research design?

**Examining gender differences in analytical problem solving skills among undergraduate students**

For which of the following situations would a repeated-measures research design be appropriate?

**Comparing patients’ pain tolerance at the beginning and at the end of physical therapy sessions**

Which of the following is the correct null hypothesis for an independent samples t-test (assume 2-tails test)?

**There is no difference between populations represented by two samples (i.e., μ1 – μ2 = 0 or μ1 = μ2).**

For which of the following situations would a repeated-measures design have the maximum advantage over an independent-measures design

**When very few subjects are available and individual differences are large.**

In a repeated-measures experiment, each individual participates in one treatment condition and then moves on to a second treatment condition. One of the major concerns in this type of study is that participation in the first treatment may influence the participant’s score in the second treatment. What is this problem called?

**Order effect.**

The t-test for independent sample can be used to examine

**The mean difference between two treatment conditions in an experiment (e.g. a difference in performance of experimental group and control group, the mean difference between two populations in quasi-experimental designs (e.g., mean difference in attitudes to abortion between residents of the southern vs. northern states in the U.S.).**

Researcher obtains t = 2.25 for a repeated-measures study using a sample of n = 10 participants. Based on this t value, what is the correct decision for a two-tailed test?

**Fail to reject the null hypothesis with either α = .05 or α = .01.**

An independent-measures study uses n = 15 participants in each group to compare two treatment conditions. What is the df value for the t statistic for this study?

**28(two groups 15 in each 15*2=30 minus 1 from each equals 28)**

The estimated standard error, s(M1-M2) in the t-test for independent samples

**Is computed based on the variances, s2 of both samples**

What is the relationship between the alpha level, the size of the critical region, and the risk of a Type I error?

**As the alpha level increases, the size of the critical region increases, and the risk of a Type I error increases.**

Which of the following research situations would be most likely to use a between-subjects research design?

**Examining gender differences in analytical problem solving skills among undergraduate students**

For which of the following situations would a repeated-measures research design be appropriate?

**Comparing patients’ pain tolerance at the beginning and at the end of physical therapy sessions**

For any distribution, what is the z-score corresponding to the median?

**This is impossible to determine based on the information provided.**

Independent Samples And Research Design – Statistic Final

On an exam with µ = 52, a person has a score of X = 44. Which value for the standard deviation would give this person the highest position in the class distribution?

**σ = 8**

Which of the following is the correct null hypothesis for an independent samples t-test (assume 2-tails test)?

**There is no difference between populations represented by two samples (i.e., μ1 – μ2 = 0 or μ1 = μ2).**

What is the average value expected for the independent-measures t statistic if the null hypothesis is true

**t = 0**

Researcher obtains t = 2.25 for a repeated-measures study using a sample of n = 10 participants. Based on this t value, what is the correct decision for a two-tailed test?

**Fail to reject the null hypothesis with either α = .05 or α = .01.**

In a population with σ = 5, a score of X = 46 corresponds to a z-score of z = +0.40. What is the population mean?

**44**

What is indicated by a large variance for a sample of difference scores (i.e., a large variance of D scores

**An inconsistent treatment effect and a low likelihood of a significant difference**

For which of the following situations would a repeated-measures design have the maximum advantage over an independent-measures design

**When very few subjects are available and individual differences are large.**

In a repeated-measures experiment, each individual participates in one treatment condition and then moves on to a second treatment condition. One of the major concerns in this type of study is that participation in the first treatment may influence the participant’s score in the second treatment. What is this problem called?

**Order effect.**

Under which circumstance is a score that is 15 points above the mean an extreme score relatively far from the mean?

**When the population standard deviation is much smaller than 15**

A population of N = 5 scores has a variance of σ 2 = 24. If the scores were from a sample, what value would be obtained for the sample variance?

**s2 = 30**

All the possible samples of n = 4 scores are selected from a population with µ = 20. If the average for all of the sample means is calculated, which value will be obtained?

**20**

In a population with σ = 5, a score of X = 46 corresponds to a z-score of z = +0.40. What is the population mean?

**44**

A population of scores has µ = 44. In this population, a score of X = 40 corresponds to z = -1.00. What is the population standard deviation?

**4**

For a sample with s = 9, a score of X = 67 corresponds to z = +1.00. What is the sample mean?

**58**

A distribution with µ = 55 and σ = 6 is being standardized so that the new mean and standard deviation will be µ = 50 and σ = 10. When the distribution is standardized, which value will be obtained for a score of X = 58 from the original distribution?

**X = 55**

For any distribution, what is the z-score corresponding to the median?

**This is impossible to determine based on the information provided.**

On an exam with µ = 52, a person has a score of X = 44. Which value for the standard deviation would give this person the highest position in the class distribution?

**σ = 8**

Researcher obtains t = 2.25 for a repeated-measures study using a sample of n = 10 participants. Based on this t value, what is the correct decision for a two-tailed test?

**Fail to reject the null hypothesis with either α = .05 or α = .01.**

Under which circumstance is a score that is 15 points above the mean an extreme score relatively far from the mean?

**When the population standard deviation is much smaller than 15**

A population of N = 5 scores has a variance of σ 2 = 24. If the scores were from a sample, what value would be obtained for the sample variance?

**s2 = 30**

In a population with σ = 5, a score of X = 46 corresponds to a z-score of z = +0.40. What is the population mean?

**44**

For any distribution, what is the z-score corresponding to the median?

**This is impossible to determine based on the information provided.**

On an exam with µ = 52, a person has a score of X = 44. Which value for the standard deviation would give this person the highest position in the class distribution?

**σ = 8**

What is the relationship between the alpha level, the size of the critical region, and the risk of a Type I error?

**As the alpha level increases, the size of the critical region increases, and the risk of a Type I error increases.**

Which of the following research situations would be most likely to use a between-subjects research design?

**Examining gender differences in analytical problem solving skills among undergraduate students**

For which of the following situations would a repeated-measures research design be appropriate?

**Comparing patients’ pain tolerance at the beginning and at the end of physical therapy sessions**

Which of the following is the correct null hypothesis for an independent samples t-test (assume 2-tails test)?

**There is no difference between populations represented by two samples (i.e., μ1 – μ2 = 0 or μ1 = μ2).**

Independent Samples And Research Design – Statistic Final