Name:
 
SPSS Worksheet 1: (t-test)
 
Instructions: Lesson 24 Exercise File 1 is located at the end of the chapter under the heading Exercises in your Green and Salkind textbook. Complete the exercise and then complete the worksheet below by filling in the blanks and answering the questions.
 
H01: There is no significant difference in the amount of time it takes to eat a Big Mac meal between overweigh and normal weight individuals.
 
Assumptions
 
Outliers: Create a Box and Whisker plot for each group. Hint: Graph > Legacy > Boxplot > Simple. Insert the Box and Whisker plot below: Note: Look for extreme outliers.
 
Fill in the blanks:

Groups

Outliers (Item #)

Are there any outliers?
 

Overweight

 
 

 

Normal

 
 

 

 
 
 
<Note: Remove any outliers from the dataset before continuing.>
 
 
Assumption of Normality: Run a normality test for each group. Hint: Begin by going to Analyze > Descriptive > Explore. See SPSS lesson 40, p. 327. Insert the Tests of Normality table below:
 
Fill in the blanks:
Should you use a Shapiro-Wilks or Kolmogorov-Smirnov test? Why?
 

Groups

Significance

Is the assumption of normality met?

Overweight

 
 

 

Normal

 
 

 

 
Assumption of Equal Variance: Insert Levene’s Test of Equality of Error Variancesa table(s) below:
 
 
Fill in the blanks:

Significance

Is the assumption of equal variance met?

 
 

 

Results
Insert t-test for equality of Means table(s) below:
 
Fill in the blanks:

Equal variances assumed

Value

d.f.

 
 

t– statistic

 
 

t- critical (Hint: See Appendix B in Warner)

 
 

p– value

 
 

Eta Squared (Hint: See formula)

 
 

 
Is the t-statistic greater than t-critical?
Hint: Use the absolute value.
 
Is the p-value less than .05?
 
Should you reject or fail to reject the null?
 
Is the effect size small, medium, or large? Hint: See Table 5.2 in Warner, p. 208.
 
 
 
 
Descriptive Statistics
Fill in the blanks:

Groups

Mean

S.D.

Overweight

 
 

 

Normal