Question

• Criterion: Calculate an independent samples t test in SPSS.
• Data: Ms Z has two groups of band students. She asks Group 1 to use her new embouchure strengthening cream before practice and asks Group 2 to practice as usual. The groups practiced for the following number of minutes:
  • Minutes of practice:
    • Group 1: 55, 44, 62, 30, 78, 50, 52.
    • Group 2: 31, 40, 53, 22, 41, 16, 33.
• Instruction: Complete the following steps:

1. Open SPSS and create a New Dataset.
2. 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 Embouchure Cream in the Label area. Click Add. Now enter 2 in the Value area and enter No Cream in the Label area. Click Add. Click OK. The Variable View screen appears.
3. In row two, enter Minutes in the Name column.
4. Click Data View.

(Assignment continues on next page.)

5. Enter the minutes of practice data (g., 1 under Groups and 55 under Minutes; 2 under Groups and 31 under Minutes).
6. In the Toolbar, click Analyze, select Compare Means, and then select Independent-Samples t Test.
7. Select Minutes, then click Arrow to send it over to the Test Variable box.
8. Select Groups and then click Arrow to send it over to the Grouping Variable box.
1. Click Define Groups and enter 1 for Group 1 and enter 2 for Group 2. Click Continue.
10. Click OK and then copy and paste the output to the Word document.

    Problem Set 6.6: 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 6.5.

    Instruction: Complete the following:

11.    Identify the IV and DV in the study.
12.    State the null hypothesis and the directional (one-tailed) alternative hypothesis.
13.    Can you reject the null hypothesis at α = .05? Explain why or why not.

Answer 1

NULL HYPOTHESIS H0:

ALTERNATIVE HYPOTHESIS Ha:

LEVEL OF SIGNIFICANCE= 0.05

IV= GROUPS UNDER 55 MINUTES AND GROUPS UNDER 35 MINUTES

DV= Effect of embouchure strengthening cream on Practice minutes.

From above table Equal Variances ASSUMED ( F=0.038 and P value=0.8940.05 therefore DO NOT REJECT H0 )

Test statistic t= 2.633

Degrees of freedom=12

P value for one tailed test= 0.022/2= 0.011

Since P value SMALLER than the level of significance therefore SIGNIFICANT

Decision: REJECT H0

Conclusion: We have sufficient evidence to show that the Mean practice time for population who applies new embouchure strengthening cream before practice is greater than the mean practice time for population who does NOT apply new embouchure strengthening cream before practice.