Independent Samples t-test

• First, assess the Normality of the variable in terms of groups.
• If both data are normal then:
  • Analyze
  • Compare means
  • Independent t-test
  • Input the test variable
  • Input the grouping variable (the group where you want differences)
    • Define groups

Output:

• Look at Levene’s Test for Equality of Variances first where two options are available
  • Equal variances assumed
  • Equal variances are not assumed
  • To know which row to choose, check the value of F in Levene’s Test for Equality of  Variances and its significance.
  • If the value of F is significant (value less than 0.05), we will take the scores on equal variance is not assumed (lower row)
  • If the value is not significant (value more than 0.05), equal variance is assumed (upper row)
  • After choosing the row, look for the significance of the t-test.
  • If it is significant then the t score indicates the difference between the two independent groups.