Homework 8

Single-Sample T-Test

When submitting this file, be sure the filename includes your full name, course and section. Example: HW8_JohnDoe_510B01

Be sure you have reviewed this module/week’s lesson and presentations along with the practice data analysis before proceeding to the homework exercises. Complete all analyses in SPSS, then copy and paste your output and graphs into your homework document file. Answer any written questions (such as the text-based questions or the APA Participants section) in the appropriate place within the same file.

Part I: Concepts

Questions 1–8; Answer the questions in the spaces provided.

Part I: Questions 1-7

Fill in the highlighted blanks with the best word or words. 2 pts each / 14 total

1) A researcher reports the results of a single-sample t-test as t(19) = 1.80. The degrees of freedom for this t-test are _______, which means there were _______total participants in the researcher’s sample.

2) Based on the previous scenario with a one-tailed test and a p level of 0.05, the critical t value is _______, meaning the researcher should _______ the null hypothesis.

3) As the sample size gets larger, the _______ distribution begin to look more like the _______ distribution.

4) The number of scores that are free to vary when you are estimating a population parameter from a sample is called the _______.

5) You use a t-test when you know the population _______ but not the population _______.

6) If t (12) = 0.79, the 0.79 represents _______.

7) If you have 8 scores, the degrees of freedom for the scores is (numerical value): _______.

Part I: Question 8

1 pt per answer = 9 pts total

8) Calculate the critical degrees of freedom and identify the critical t value for a single-sample t test in each of the following situations. Then, state whether the null hypothesis would be accepted or rejected:

8A) Two-tailed test, N = 12, t = 1.85, p = .10 df= Answer critical t = Answer

Accept or Reject Ho: Answer

8B) Two-tailed test, N = 18, t = 1.85, p = .05 df= Answer critical t = Answer

Accept or Reject Ho: Answer

8C) One-tailed test, N = 27, t = 1.85, p = .01 df= Answer critical t = Answer

Accept or Reject Ho: Answer

Part II: SPSS Analysis

Module/Week 8 Exercise File 1

Open the “Module/Week 8 Exercise File 1” document (found in the course’s Assignment Instructions folder) in order to complete these exercises. Part II: Exercises 1-3 (16 pts)

Use file: Homework8DataFile

The memory scores for 15 fictional patients with dementia are entered in the “Homework8DataFile” SPSS document (found in the Assignment Instructions folder).

Higher memory number indicates better memory performance.

Using these data, run 2 single-sample t-tests to compare the dementia patients’ mean memory score to the following population values:

Population memory scores

Age-matched controls: = 12.2

Patients with traumatic brain injury (TBI): = 8.1

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 2 sets of output and 2 results sections using this data set

1 for each test involving a different population mean.

1) Using the “explore” tab, run descriptive statistics on the dementia patients’ memory scores (make sure to include the mean and confidence interval). 2pts

Answer: SPSS output of descriptive statistics

2A) Population of age matched controls: = 12.2. 2pts

Answer: SPSS output of the t-Test

2B) Calculate the effect size for the one-sample t test as shown in the Green and Salkind textbook, Lesson 22.2 using the formula: d = Mean Difference / SD. Show all work. 2pts

Answer

Work

2C) Write a results section in current APA style describing the outcome.

All homework results sections must follow the example given in the SPSS presentation and in the textbook. Results sections are multiple sentences (a single paragraph) and must include the APA-formatted statistical statement within a sentence. 3pts

Answer

3A) Population of patients with TBI: = 8.1. 2pts

Answer: SPSS output of the t-Test

3B) Calculate the effect size for the one-sample t test as shown in the Green and Salkind textbook, Lesson 22.2 using the formula: d = Mean Difference / SD. Show all work. 2pts

Answer

Work

3C) Write a results section in current APA style describing the outcome. See (2C) for details. 3pts

Answer

Part III: SPSS Data Entry and Analysis

Data provided below.

Attitudes Toward

Technology Scale Scores

21

23

20

18

17

20

24

21

19

17

20

Part III: Question 1A-E

11 pts

Do elderly people have less positive attitudes toward technology than people in general?

A social psychologist assessed the attitudes of 11 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 23.1. The data for the participants are shown in the table to the left.

Using SPSS, conduct a single-sample t-test to answer the social psychologist’s research question.

1A) Paste appropriate descriptive statistics table here (must include mea annd confidence intervals) 2pts

Answer: SPSS output of descriptive statistics

1B) Paste one sample t-test output here for = 23.1 / 2pts

Answer: SPSS output of the t-Test

1C) Using the directions in Part II, calculate the effect size. 2pts

Answer Work

1D) Paste appropriate SPSS graph to show the distribution of elderly attitudes 2pts

Answer: SPSS graph

1E) Write a results section in current APA style describing the outcome. Refer to earlier directions for details of what is expected. 3pts

Answer:

Part IV: Cumulative

Data provided below for respective questions. Part IV: Question 1 (Non-SPSS) (3 pts)

Age at onset of dementia was determined in the general population to be = 69.5 and = 2.8.

Use this information to answer the following:

1A) Based on the data above, what is the z score for the age of 65? (1pt)

Answer Work:

1B) Based on the data you have and the z table, what percentage of people might start to show signs of dementia at or before age 65? (2 pts)

Answer

Part IV: Question 2-7 (Non-SPSS)

2 pts each / 12 pts total

Fill in the highlighted blanks with the best word or words. 2 pts each / 14 total

2) If you have a known population mean and standard deviation to compare to one sample, you can perform a _______.

3) A probability of 0.35 converts to a percent of _______.

4) If a researcher concludes that their intervention had no effect when in fact it did, they make a _______error.

5) The _______ hypothesis states that there is an average (nonsignificant) difference between populations.

6) The three measures of central tendency are the _______, _______, and _______.

7) If there is one scale independent variable and one scale dependent variable use a _______ or a _______.

Submit Homework 8 by 11:59 p.m. (ET) on Friday of Module/Week 8. Remember to name file appropriately.

Done!

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