Correlations
The scatter plots and correlation coefficient for the variables GMAT Score and Overall GPA are shown below.
From running a regression analysis on Spss, the multiple R or rather the Pearson correlation coefficient was found to be with a p value of 0.044. Using an alpha of , we can tell that the correlation is significant as is less than .Therefore, GMAT scores have a weak linear correlation with GPA which is significant. This can further be illustrated by the scatter plot as there seems to be a slight increase in GPA as GMAT scores increase.
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The scatter plots and correlation coefficient of the variables Starting salary and GMAT score.
From the regression analysis on Spss, the Pearson correlation coefficient (R) between the two variables is and the p value is 0.181. Therefore, the GMAT score and starting salary have a very weak negative linear correlation that is insignificant using an alpha of . This can further be illustrated by the scatter plot, though not clearly but there seems to general slight decrease salaries as the GMAT scores increases.
The scatter plots and correlation coefficient of the variables Starting salaries and Overall GPA are shown below.
From Spss, the Pearson correlation coefficient (R) between the overall GPA and the starting salary is with a p-value of . Therefore, there is a very weak and barely visible negative linear correlation between the two variables and since the p-value is more than the alpha level, the correlation is not significant.
The scatter plots and correlation coefficient of the variables starting salaries and years of experience are shown below.
From Spss, the Pearson correlation coefficient between the two variables, starting salaries and years of experience is with a p-value of . The p-value is significantly lower than the alpha of . Therefore, indicating the correlation is significant. Moreover, the two variables have a relatively strong positive linear correlation. The scatter plot illustrates this by showing a slightly visible increase in salary as years of experience increase.
Creating a Salary Model
After running a multiple regression analysis, with Starting salaries as the dependent variable and GMAT score, Overall GPA and work experience as the independent variables, work experience showed the strongest correlation as well as was the only significant independent variable that determined the Starting salaries. This is because it had a p-value of which is less than alpha of . The GMAT score and Overall GPA do not have a significant relationship with the starting salary.
The inclusion of Gender_DV changes the overall Pearson correlation coefficient from to . It therefore increases the positive linear correlation between the Starting salaries and the other three independent variables, GMAT score, Overall GPA and work experience.
Running the multiple regression analysis using the independent variables Gender_GMAT, Gender_GPA and Gender_WorkYear, there is a general improvement in the Pearson correlation coefficients of the Gender_GMAT scores and Gender_GPA. The Pearson correlation coefficients are and . The two variables also become significant in determining the Starting salaries as they have p-values of and respectively which are both lower than the alpha value . However, the Pearson correlation coefficient of the Gender-work year decreases to indicating a weaker positive linear correlation between the it and the Starting salaries. It however, remains a significant variable.
From the Spss analysis and using stepwise regression the final model of the regression is
The coefficient of Gender_workyear has a standard error of and the constant has a standard error of .
Limitations of the analysis
From the analysis, what we are not sure about is whether the graduates come out of school and go into employment in their own or family businesses or apply for jobs directly. Moreover, the graduates could go into different firms that are in different fields or are government institutions. Different firms have different income levels which means the salaries they get paid even if they are in the same position could be different.
Appendix
Correlations |
|||||
Salary |
GMAT_TOT |
GPA |
Work_Yrs |
||
Pearson Correlation | Salary |
1.000 |
-.091 |
-.018 |
.455 |
GMAT_TOT |
-.091 |
1.000 |
.169 |
-.123 |
|
GPA |
-.018 |
.169 |
1.000 |
-.060 |
|
Work_Yrs |
.455 |
-.123 |
-.060 |
1.000 |
|
Sig. (1-tailed) | Salary |
. |
.181 |
.428 |
.000 |
GMAT_TOT |
.181 |
. |
.044 |
.108 |
|
GPA |
.428 |
.044 |
. |
.272 |
|
Work_Yrs |
.000 |
.108 |
.272 |
. |
|
N | Salary |
103 |
103 |
103 |
103 |
GMAT_TOT |
103 |
103 |
103 |
103 |
|
GPA |
103 |
103 |
103 |
103 |
|
Work_Yrs |
103 |
103 |
103 |
103 |
Table 1 Table showing regression analysis of salary as dependent variable and GMAT scores, Overall GPA and years of experience as the independent variables.
Model Summary b |
|||||
Model |
R |
R Square |
Adjusted R Square |
Std. Error of the Estimate |
Durbin-Watson |
1 |
.456 a |
.208 |
.184 |
16139.492 |
1.188 |
a. Predictors: (Constant), Work_Yrs, GPA, GMAT_TOT | |||||
b. Dependent Variable: Salary |
Table 2 Model summary of the table 1 regression analysis
Coefficients a |
|||||||||||||
Model |
Unstandardized Coefficients |
Standardized Coefficients |
t |
Sig. |
95.0% Confidence Interval for B |
Correlations |
Collinearity Statistics |
||||||
B |
Std. Error |
Beta |
Lower Bound |
Upper Bound |
Zero-order |
Partial |
Part |
Tolerance |
VIF |
||||
1 | (Constant) |
99102.674 |
22536.518 |
4.397 |
.000 |
54385.333 |
143820.016 |
||||||
GMAT_TOT |
-13.359 |
32.196 |
-.038 |
-.415 |
.679 |
-77.243 |
50.525 |
-.091 |
-.042 |
-.037 |
.959 |
1.043 |
|
GPA |
746.134 |
4392.102 |
.015 |
.170 |
.865 |
-7968.750 |
9461.017 |
-.018 |
.017 |
.015 |
.970 |
1.031 |
|
Work_Yrs |
2676.588 |
535.316 |
.451 |
5.000 |
.000 |
1614.405 |
3738.770 |
.455 |
.449 |
.447 |
.983 |
1.017 |
|
a. Dependent Variable: Salary |
Table 3 Coefficients of table 1
Correlations |
||||||
Salary |
GMAT_TOT |
GPA |
Work_Yrs |
Gender_DV |
||
Pearson Correlation | Salary |
1.000 |
-.091 |
-.018 |
.455 |
.166 |
GMAT_TOT |
-.091 |
1.000 |
.169 |
-.123 |
.020 |
|
GPA |
-.018 |
.169 |
1.000 |
-.060 |
-.152 |
|
Work_Yrs |
.455 |
-.123 |
-.060 |
1.000 |
.092 |
|
Gender_DV |
.166 |
.020 |
-.152 |
.092 |
1.000 |
|
Sig. (1-tailed) | Salary |
. |
.181 |
.428 |
.000 |
.047 |
GMAT_TOT |
.181 |
. |
.044 |
.108 |
.422 |
|
GPA |
.428 |
.044 |
. |
.272 |
.063 |
|
Work_Yrs |
.000 |
.108 |
.272 |
. |
.177 |
|
Gender_DV |
.047 |
.422 |
.063 |
.177 |
. |
|
N | Salary |
103 |
103 |
103 |
103 |
103 |
GMAT_TOT |
103 |
103 |
103 |
103 |
103 |
|
GPA |
103 |
103 |
103 |
103 |
103 |
|
Work_Yrs |
103 |
103 |
103 |
103 |
103 |
|
Gender_DV |
103 |
103 |
103 |
103 |
103 |
Table 4 Table showing the regression analysis with Gender_DV inclusion
Model Summary b |
|||||
Model |
R |
R Square |
Adjusted R Square |
Std. Error of the Estimate |
Durbin-Watson |
1 |
.474 a |
.225 |
.193 |
16047.860 |
1.163 |
a. Predictors: (Constant), Gender_DV, GMAT_TOT, Work_Yrs, GPA | |||||
b. Dependent Variable: Salary |
Table 5 Model summary of Table 4
Coefficients a |
|||||||||||||
Model |
Unstandardized Coefficients |
Standardized Coefficients |
t |
Sig. |
95.0% Confidence Interval for B |
Correlations |
Collinearity Statistics |
||||||
B |
Std. Error |
Beta |
Lower Bound |
Upper Bound |
Zero-order |
Partial |
Part |
Tolerance |
VIF |
||||
1 | (Constant) |
94333.329 |
22645.176 |
4.166 |
.000 |
49394.713 |
139271.945 |
||||||
GMAT_TOT |
-16.006 |
32.065 |
-.045 |
-.499 |
.619 |
-79.637 |
47.625 |
-.091 |
-.050 |
-.044 |
.956 |
1.046 |
|
GPA |
1741.509 |
4420.007 |
.036 |
.394 |
.694 |
-7029.850 |
10512.869 |
-.018 |
.040 |
.035 |
.947 |
1.056 |
|
Work_Yrs |
2606.092 |
534.460 |
.439 |
4.876 |
.000 |
1545.474 |
3666.710 |
.455 |
.442 |
.434 |
.975 |
1.025 |
|
Gender_DV |
5121.062 |
3505.769 |
.132 |
1.461 |
.147 |
-1836.023 |
12078.146 |
.166 |
.146 |
.130 |
.967 |
1.034 |
|
a. Dependent Variable: Salary |
Table 6 Coefficients of table 4
Correlations |
|||||
Salary |
Gender_GMAT |
Gender_GPA |
Gender_WorkYear |
||
Pearson Correlation | Salary |
1.000 |
.173 |
.192 |
.206 |
Gender_GMAT |
.173 |
1.000 |
.967 |
.549 |
|
Gender_GPA |
.192 |
.967 |
1.000 |
.544 |
|
Gender_WorkYear |
.206 |
.549 |
.544 |
1.000 |
|
Sig. (1-tailed) | Salary |
. |
.041 |
.026 |
.018 |
Gender_GMAT |
.041 |
. |
.000 |
.000 |
|
Gender_GPA |
.026 |
.000 |
. |
.000 |
|
Gender_WorkYear |
.018 |
.000 |
.000 |
. |
|
N | Salary |
103 |
103 |
103 |
103 |
Gender_GMAT |
103 |
103 |
103 |
103 |
|
Gender_GPA |
103 |
103 |
103 |
103 |
|
Gender_WorkYear |
103 |
103 |
103 |
103 |
Table 7 Regression analysis using independent variables influenced by gender in determining the dependent variable Starting salaries
Variables Entered/Removed a |
|||
Model |
Variables Entered |
Variables Removed |
Method |
1 | Gender_WorkYear |
. |
Stepwise (Criteria: Probability-of-F-to-enter <= .050, Probability-of-F-to-remove >= .100). |
a. Dependent Variable: Salary |
Table 8 table indicating variables removed after doing stepwise regression
Model Summary b |
|||||
Model |
R |
R Square |
Adjusted R Square |
Std. Error of the Estimate |
Durbin-Watson |
1 |
.206 a |
.043 |
.033 |
17571.151 |
.855 |
a. Predictors: (Constant), Gender_WorkYear | |||||
b. Dependent Variable: Salary |
Table 9 Model summary after doing stepwise regression of table 7
Coefficients a |
|||||||||||||
Model |
Unstandardized Coefficients |
Standardized Coefficients |
t |
Sig. |
95.0% Confidence Interval for B |
Correlations |
Collinearity Statistics |
||||||
B |
Std. Error |
Beta |
Lower Bound |
Upper Bound |
Zero-order |
Partial |
Part |
Tolerance |
VIF |
||||
1 | (Constant) |
99873.058 |
2284.889 |
43.710 |
.000 |
95340.452 |
104405.663 |
||||||
Gender_WorkYear |
1169.932 |
552.434 |
.206 |
2.118 |
.037 |
74.050 |
2265.813 |
.206 |
.206 |
.206 |
1.000 |
1.000 |
|
a. Dependent Variable: Salary |
Table 10 Coefficients of table 7 after doing stepwise regression of table 7