Data Analysis Using SPSS T-Test
Transcript of Data Analysis Using SPSS T-Test
Data Analysis Using Data Analysis Using SPSSSPSS
t-testt-test
t-testt-test Used to test whether there is Used to test whether there is
significant difference between the significant difference between the means of two groups, e.g.:means of two groups, e.g.:• Male v female Male v female • Full-time v part-time Full-time v part-time
t-testt-test Typical hypotheses for t-test:Typical hypotheses for t-test:
a)a) There is no difference in affective There is no difference in affective commitment (affcomm) between male commitment (affcomm) between male and female employeesand female employees
b)b) There is no difference in continuance There is no difference in continuance commitment (concomm) between male commitment (concomm) between male and female employeesand female employees
c)c) There is no difference in normative There is no difference in normative commitment (norcomm) between male commitment (norcomm) between male and female employeesand female employees
Performing T-testPerforming T-test
Analyze Analyze → → Compare Means → Compare Means →
Independent-Samples T-testIndependent-Samples T-test
Performing T-testPerforming T-test Select the variables to test (Test Select the variables to test (Test
Variables), in this case:Variables), in this case:• affcommaffcomm• concommconcomm• norcommnorcomm
And bring the variables to the “Test And bring the variables to the “Test Variables” boxVariables” box
Performing T-testPerforming T-test Select the grouping variable, i.e. Select the grouping variable, i.e.
gender; bring it to the “grouping gender; bring it to the “grouping variable” boxvariable” box
Click “Define Groups”Click “Define Groups”
Performing T-testPerforming T-test Choose “Use specified values”Choose “Use specified values” Key in the codes for the variable Key in the codes for the variable
“gender” as used in the “Value “gender” as used in the “Value Labels”. In this case:Labels”. In this case:1 - Male1 - Male2 - Female 2 - Female
Click “Continue”, then “OK”Click “Continue”, then “OK”
T-Test: SPSS Output
Group Statistics
357 3.49720 .731988 .038741315 3.38016 .696273 .039231357 3.18838 .756794 .040054315 3.15159 .666338 .037544357 3.24090 .665938 .035245315 3.27540 .647409 .036477
GENDER OFRESPONDENTMALEFEMALEMALEFEMALEMALEFEMALE
affcomm
concomm
norcomm
N Mean Std. DeviationStd. Error
Mean
Independent Samples Test
1.048 .306 2.116 670 .035 .117040 .055308 .008442 .225638
2.123 666.213 .034 .117040 .055135 .008780 .225300
5.353 .021 .665 670 .506 .036788 .055335 -.071863 .145440
.670 669.997 .503 .036788 .054899 -.071006 .144582
.656 .418 -.679 670 .497 -.034500 .050813 -.134272 .065271
-.680 663.726 .497 -.034500 .050723 -.134097 .065096
Equal variancesassumedEqual variancesnot assumedEqual variancesassumedEqual variancesnot assumedEqual variancesassumedEqual variancesnot assumed
affcomm
concomm
norcomm
F Sig.
Levene's Test forEquality of Variances
t df Sig. (2-tailed)Mean
DifferenceStd. ErrorDifference Lower Upper
95% ConfidenceInterval of the
Difference
t-test for Equality of Means
T-test: SPSS Output
From the SPSS output, we are able From the SPSS output, we are able to see that the means of the to see that the means of the respective variables for the two respective variables for the two groups are:groups are:
• Affective commitment (affcomm) Affective commitment (affcomm) Male 3.49720 Female 3.38016Male 3.49720 Female 3.38016
• Continuance commitment (concomm)Continuance commitment (concomm) Male 3.18838 Female 3.15159Male 3.18838 Female 3.15159
• Normative commitment (norcomm)Normative commitment (norcomm) Male 3.24090 Female 3.27540Male 3.24090 Female 3.27540
T-test: InterpretationT-test: Interpretation For the variable “affcomm”For the variable “affcomm”
• Levene’s Test for Equality of Variances Levene’s Test for Equality of Variances shows that F (1.048) is not significant shows that F (1.048) is not significant (0.306)* therefore the “Equal variances (0.306)* therefore the “Equal variances assumed” row will be used for the t-test.assumed” row will be used for the t-test.
* This score (sig.) has to be 0.05 or less to be * This score (sig.) has to be 0.05 or less to be considered significant.considered significant.
T-test: InterpretationT-test: Interpretation Under the “t-test for Equality of Under the “t-test for Equality of
Means” look at “Sig. (2-tailed)” Means” look at “Sig. (2-tailed)” for “Equal variances assumed”. for “Equal variances assumed”.
The score is 0.035 (which is less The score is 0.035 (which is less than 0.05), therefore there is a than 0.05), therefore there is a significant difference between significant difference between the means of the two groups.the means of the two groups.
Independent Samples Test
1.048 .306 2.116 670 .035 .117040 .055308 .008442 .225638
2.123 666.213 .034 .117040 .055135 .008780 .225300
5.353 .021 .665 670 .506 .036788 .055335 -.071863 .145440
.670 669.997 .503 .036788 .054899 -.071006 .144582
.656 .418 -.679 670 .497 -.034500 .050813 -.134272 .065271
-.680 663.726 .497 -.034500 .050723 -.134097 .065096
Equal variancesassumedEqual variancesnot assumedEqual variancesassumedEqual variancesnot assumedEqual variancesassumedEqual variancesnot assumed
affcomm
concomm
norcomm
F Sig.
Levene's Test forEquality of Variances
t df Sig. (2-tailed)Mean
DifferenceStd. ErrorDifference Lower Upper
95% ConfidenceInterval of the
Difference
t-test for Equality of Means
T-test: Interpretation
T-test: InterpretationT-test: Interpretation For the variable “concomm”For the variable “concomm”
• Levene’s Test for Equality of Variances Levene’s Test for Equality of Variances shows that F (5.353) is significant shows that F (5.353) is significant (0.021)* therefore the “Equal variances (0.021)* therefore the “Equal variances not assumed” row will be used for the t-not assumed” row will be used for the t-test.test.
* This score (sig.) is less than 0.05, so there is * This score (sig.) is less than 0.05, so there is significant different in the variances of the significant different in the variances of the two groups.two groups.
T-test: InterpretationT-test: Interpretation Under the “t-test for Equality of Under the “t-test for Equality of
Means” look at “Sig. (2-tailed)” for Means” look at “Sig. (2-tailed)” for “Equal variances not assumed”. “Equal variances not assumed”.
The score is 0.503 (which is more The score is 0.503 (which is more than 0.05), therefore there is no than 0.05), therefore there is no significant difference between the significant difference between the means of the two groups.means of the two groups.
Independent Samples Test
1.048 .306 2.116 670 .035 .117040 .055308 .008442 .225638
2.123 666.213 .034 .117040 .055135 .008780 .225300
5.353 .021 .665 670 .506 .036788 .055335 -.071863 .145440
.670 669.997 .503 .036788 .054899 -.071006 .144582
.656 .418 -.679 670 .497 -.034500 .050813 -.134272 .065271
-.680 663.726 .497 -.034500 .050723 -.134097 .065096
Equal variancesassumedEqual variancesnot assumedEqual variancesassumedEqual variancesnot assumedEqual variancesassumedEqual variancesnot assumed
affcomm
concomm
norcomm
F Sig.
Levene's Test forEquality of Variances
t df Sig. (2-tailed)Mean
DifferenceStd. ErrorDifference Lower Upper
95% ConfidenceInterval of the
Difference
t-test for Equality of Means
T-test: Interpretation
T-test: InterpretationT-test: Interpretation For the variable “norcomm”For the variable “norcomm”
• Levene’s Test for Equality of Variances Levene’s Test for Equality of Variances shows that F (0.656) is not significant shows that F (0.656) is not significant (0.418)* therefore the “Equal variances (0.418)* therefore the “Equal variances are assumed” row will be used for the t-are assumed” row will be used for the t-test.test.
* This score (sig.) is more than 0.05, so there * This score (sig.) is more than 0.05, so there is no significant different in the variances of is no significant different in the variances of the two groups.the two groups.
T-test: InterpretationT-test: Interpretation Under the “t-test for Equality of Under the “t-test for Equality of
Means” look at “Sig. (2-tailed)” for Means” look at “Sig. (2-tailed)” for “Equal variances assumed”. “Equal variances assumed”.
The score is 0.497 (which is more The score is 0.497 (which is more than 0.05), therefore there is no than 0.05), therefore there is no significant difference between the significant difference between the means of the two groups.means of the two groups.