PSYC4700- Statistics for the Behavioral Sciences

PSYC4700 – Statistics for the Behavioral Sciences

## u06a

1

– t Tests

Complete the following problems within the Word document. (Do not submit other files.) Show your work for problem sets that require calculations. Ensure that your answer to each problem is clearly visible. (You may want to highlight your answer or use a different type of color to set it apart.)

Submit the document to your instructor by Sunday, 11:59 p.m. central time.

Problem Set 6.1: One-Sample t Test in SPSS

Criterion: Calculate a one-sample t test in SPSS.

Data: Riverbend City online news advertises that it is read longer than the national news. The mean for national news is 8 hours per week. The following sample of the Riverbend City online news readers is: 5, 7, 6, 2, 4, 8, 5, 4, 18, 21, 8, 7, 4, 5, 6.

Instructions: Complete the following:

a. Enter the data from Problem Set 6.1 into SPSS and name the variable as Roses.

b. In the Toolbar, click Analyze, select Compare Means, and then select One-Sample t Test.

c. Select Roses, then click Arrow to send it over to the right side of the table. In the box labeled Test Value, enter 8.

d. Click OK and copy and paste the output into the Word document.

e. State the nondirectional hypothesis.

f. State the critical t for a = .05 (two tails).

g. Answer the following: Is the length of viewing for Riverbend City online news significantly different than the population mean? Explain.

##### Problem Set 6.2: Confidence Intervals

Criterion: Calculate confidence intervals using SPSS.

Data: Use the SPSS output from Problem Set 6.2 above.

Instructions: Based on the SPSS output from Problem Set 6.2, including a test value (population mean) of 14, calculate the 95% confidence interval.

#### Problem Set 6.3: Independent t Test in SPSS

Criterion: Calculate an independent samples t test in SPSS.

Data: Dr. Z divides her clients with depression into 2 groups. She asks Group 1 not to watch or read any news for two weeks while in therapy and asks Group 2 to continue with therapy as normal. The groups scored the following on measure of depression:

Minutes of practice:

Group 1: 34, 25, 4, 64, 14, 49, 54

Group 2: 24, 78, 59, 68, 84, 79, 57

Instructions: Complete the following steps:

a. Open SPSS and create a New Dataset.

b. Click the Variable View tab and type Groups in the Name column. Click on the gray box in the Values column. Value Labels window appears. Enter 1 in the Value area and enter No News in the Label area. Click Add. Now enter 2 in the Value area and enter Treatment Only in the Label area. Click Add. Click OK. The Variable View screen appears.

c. In row two, enter Scores in the Name column.

d. Click Data View.

e. Enter the minutes of practice data (e.g., 1 under Groups and 34 under Scores; 2 under Groups and 24 under Scores).

f. In the Toolbar, click Analyze, select Compare Means, and then select Independent-Samples t Test.

g. Select Scores, then click Arrow to send it over to the Test Variable box.

h. Select Groups and then click Arrow to send it over to the Grouping Variable box.

i. Click Define Groups and enter 1 for Group 1 and enter

2

for Group 2. Click Continue.

j. Click OK and then copy and paste the output to the Word document.

Problem Set 6.4: Independent Samples t Test

Criterion: Identify IV, DV, and hypotheses and evaluate the null hypothesis for an independent samples t test.

Data: Use the information from Problem Set 6.3.

Instructions: Complete the following:

a. Identify the IV and DV in the study. _____________________________________

b. State the null hypothesis and the directional (one-tailed) alternative hypothesis. ___________________________________________________

c. Can you reject the null hypothesis at α = .05? Explain why or why not. ___________________________________________________

Problem Set 6.5: Independent t Test using Excel

Criterion: Calculate an independent samples t test in Excel.

Instructions: Complete the following steps:

a. Open Excel.

b. On an empty tab, enter the data from Problem Set 6.3. Use column A for group 1 and column B for Group 2. In Cell A1, enter 1. In cell B1, enter 2.

c. Enter the data for each group below the label.

d. Click Data Analysis, select t-Test: Two-Sample Assuming Equal Variances. Click OK.

e. In Variable 1 Range enter $A$2:$A$8. (Or, click the graph icon at the right of the box and highlight your data for Group 1. Then, click the graph icon.)

f. In Variable 2 Range enter $B$2:$B$8.

g. Then click OK. Your results will appear on a new tab to the left.

h. Return to your data. Click Data Analysis, select t-Test: Two-Sample Assuming Unequal Variances. Then click OK.

i. In Variable 1 Range enter $A$2:$A$8. (Or, click the graph icon at the right of the box and highlight your data for Group 1. Then, click the graph icon.)

j. In Variable 2 Range enter $B$2:$B$8.

k. Then click OK. Your results will appear on a new tab to the left.

l. Copy the results from both t tests below.

Problem Set 6.6: Determine Statistical Test for Project

Criterion: Determine a statistical test to use for a project based on type of data, sample, and purpose.

Instructions: Answer the following questions.

a. My first variable is named: ___________

b. My first variable is (nominal, ordinal, interval/ration): ___________

c. My second variable is named: ___________

d. My second variable is (nominal, ordinal, interval/ration): ___________

e. How many samples do I have: ___________

f. What is the purpose of my study: ___________

g. The type of statistical I will use is: ___________

1

1