PSYC354 HOMEWORK 8

Homework 8

Single-Sample T-Test

Be sure you have reviewed this module/week’s lessons and presentations along with the practice data analysis before proceeding to the homework exercises. Complete all analyses in SPSS, and then copy and paste your output and graphs into your homework document file. Number all responses. Answer any written questions (such as the text-based questions or the APA Participants section) in the appropriate place within the same file. Review the “Homework Instructions: General” document for an example of how homework assignments must look.

Part I: Concepts

1. Fill in the blanks with the correct word or words.

a. You use a t-test when you know the population ____ but not the population __

b. The t-statistic indicates the distance of a sample mean from the ________ in terms of estimated standard error units.

c. The 2 groups compared in the single-sample t-test are the sample and the ___

d. The number of scores that are free to vary when you are estimating a population parameter from a sample is called the ___ __.

e. A researcher reports the results of a single-sample t-test as t(19) = 2.13. There were ______ total participants in the researcher's sample.

f. The critical values of the t-statistic for a two-tailed test with df = 6 and a p level of 0.05 are ___+

g. When our t-statistic exceeds your critical cutoffs, you the null hypothesis.

2. Complete the following Nolan and Heinzen end-of-chapter exercises for Chapter 9: 9.10 and 9.24. If applicable, remember to show work in your homework document to receive partial credit.

9.10 Explain what each part of the following statistical phrase

means, as it would be reported in APA format: t(4) ? 2.87, p ? 0.032.

9.24 Calculate degrees of freedom and identify the critical t

value for a single-sample t test in each of the following

circumstances:

a. Two-tailed test, N ? 8, p level of 0.10

b. One-tailed test, N ? 42, p level of 0.0

c. Two-tailed test, N ? 89, p level of 0.01 +

Part II: SPSS Analysis

1. End-of-chapter exercise 9.37 in Nolan and Heinzen describes a study of anger and mood in a sample of 60 Marines following a month-long intense training exercise. The scores for 6 fictional Marines are entered in the Module/Week 8 Exercise File 1 document (found in the Assignment Instructions folder). Using these data, run 3 single-sample t-tests to compare the Marines’ mean score to the following population values:

a. Population of college men: mu = 8.9

b. Population of adult men: mu = 9.2

Population of male psychiatric outpatients: mu = 13.5

For each test, paste the output and write a results section in current APA style (as demonstrated in the presentation and in the textbooks). There will be 3 sets of output and 3 results sections (1 for each test involving a different population mean).

Part III: SPSS Data Entry and Analysis

1. A clinical psychologist is treating 12 patients with clinical depression. She wants to find out whether these patients score differently than the general population on an emotional response scale (ERS) with a population mean ? = 9.5. She is only interested in whether there is a difference but not in the direction of the difference at this point. The table below contains the scores of the patients. Conduct a single-sample t-test to evaluate the claim that these patients score differently than the general population on the ERS.

a. Paste appropriate SPSS output here.

b. Paste appropriate SPSS graph here.

c. Write a results section in current APA style describing the outcome. All homework results sections must follow the example given in the Module/Week 8 presentation “APA Writing 3 – The Complete Results Section.”

Do elderly people have less positive attitudes toward technology than people in general? A social psychologist assessed the attitudes of 15 elderly people using a scale where a lower score indicates a less positive attitude overall. The mean on this scale for the general population is 16.8. The data for the participants are shown in the table below. Using SPSS, conduct a single-sample t-test to answer the social psychologist’s research question.

Attitudes Toward Technology Scale Scores

12 17 9 11 12 12 5 8 15 6 5 7 9 14 10

a. Paste appropriate SPSS output here.

b. Paste appropriate SPSS graph here.

c. Write a results section in current APA style describing the outcome. All homework results sections must follow the example given in the presentation.

Part IV: Cumulative

1. (Non-SPSS) Age at onset of dementia was determined for a sample of adults between the ages of 60 and 75. For 15 subjects, M = 67.2 and s = 3.06. Use this information to answer the following:

a. Based on the data you have and the normal curve tables, what percentage of people might start to show signs of dementia at or before age 62? (

b. If you consider the normal range of onset in this population to be +/-1 z-score from the mean, what two ages correspond to this?

c. A neuropsychologist is interested only in studying the most deviant portion of this population: those individuals who fall within the top 10% and the bottom 10% of the distribution. She must determine the ages that mark these boundaries. What are these ages?

2. (Non-SPSS) For each of the following scenarios, compute the effect size and state (whether it is approximately small, medium, or large).

a. Participants in an inpatient study of treatment for OCD complete an anxious feelings inventory which is then compared to the general population. The sample mean is M = 27.2. The mean in the general population of inpatients on this inventory is M = 35.5, and the population standard deviation is 1.9. -

b. A mood assessment in a sample of 15 gym members has a mean of 87 and a standard deviation of 6. The mean in the general population on this measure is 79.