(a) Using a multiple regression analysis explore the effects of the independent variables on TIME 1.
Descriptive Statistics
Mean
Std. Deviation
N
time1
99.69
105.697
252
group
1.50
.501
252
enthusiasm for task
2.50
1.120
252
age
21.81
4.151
252
gender
1.38
.486
252
hand2
1.68
.468
252
dumgroup
.50
.501
252
The result of the descriptive chart is showing the mean of the dependent variable that is the first trial after drinking of coffee or decaffeinated substitute is 99.69 and standard deviation is 105.69, and the mean and standard deviation of independent variables are also mentioned in the above table.
Model Summaryb
Model
R
R Square
Adjusted R Square
Std. Error of the Estimate
Change Statistics
R Square Change
F Change
df1
df2
Sig. F Change
1
.404a
.163
.146
97.652
.163
9.612
5
246
.000
a. Predictors: (Constant), dumgroup, gender, hand2, enthusiasm for task, age
b. Dependent Variable: time1
ANOVAb
Model
Sum of Squares
df
Mean Square
F
Sig.
1
Regression
458281.756
5
91656.351
9.612
.000a
Residual
2345849.716
246
9535.974
Total
2804131.472
251
a. Predictors: (Constant), dumgroup, gender, hand2, enthusiasm for task, age
b. Dependent Variable: time1
The above charts are showing that the significant value of ANOVA table is less than 0.05 and the value of R is 40.4 % and the value of R-square is 16.3 % that means there is a relationship between the dependent variable that is the first trial after drinking of coffee or decaffeinated substitute and the independent variables.
Coefficientsa
Model
Un-standardized Coefficients
Standardized Coefficients
t
Sig.
Collinearity Statistics
B
Std. Error
Beta
Tolerance
VIF
1
(Constant)
14.205
38.627
.368
.713
enthusiasm for task
6.594
5.688
.070
1.159
.247
.936
1.069
age
-4.670
1.626
-.183
-2.872
.004
.834
1.199
gender
77.153
13.222
.354
5.835
.000
.922
1.085
hand2
26.755
13.925
.118
1.921
.056
.895
1.118
dumgroup
39.122
12.723
.185
3.075
.002
.935
1.069
a. Dependent Variable: time1
From the above table, it can be understood that there is not too much multicolinearity between the variables because the values of tolerance and VIF are near to 1 which is a good indication. Moreover the beta values of all the independent variables are positive, but age is in negative that shows there is a negative relationship of the first trial after drinking of coffee with the age. However, there is a positive relationship between the first trials of coffee with the other independent variables (Keith, 2006, pp. 12-32).
(b) Using a multiple regression analysis explore the effects of the independent variables on TIME 10.
Descriptive Statistics
Mean
Std. Deviation
N
time10
9.21
4.792
252
group
1.50
.501
252
enthusiasm for task
2.50
1.120
252
age
21.81
4.151
252
gender
1.38
.486
252
hand2
1.68
.468
252
dumgroup
.50
.501
252
The result of the descriptive chart is showing the mean of the dependent variable that is third trial after drinking of coffee or decaffeinated substitute is 9.21 and standard deviation is 4.79, and the mean and standard deviation of independent variables also mentioned in the above table.
Model Summaryb
Model
R
R Square
Adjusted R Square
Std. Error of the Estimate
Change Statistics
R Square Change
F Change
df1
df2
Sig. F Change
1
.439a
.193
.176
4.349
.193
11.748
5
246
.000
a. Predictors: (Constant), dumgroup, gender, hand2, enthusiasm for task, age
b. Dependent Variable: time10
ANOVAb
Model
Sum of Squares
df
Mean Square
F
Sig.
1
Regression
1110.868
5
222.174
11.748
.000a
Residual
4652.402
246
18.912
Total
5763.270
251
a. Predictors: (Constant), dumgroup, gender, hand2, enthusiasm for task, age
b. Dependent Variable: time10
The above charts are showing that the significant value of ANOVA table is less than 0.05 and the value of R is 43.9 % and the value of R-square is 194.3 % that means there is a relationship between the dependent variable that is the third trial after drinking of coffee or decaffeinated substitute and the independent variables.
Coefficientsa
Model
Unstandardized Coefficients
Standardized Coefficients
t
Sig.
Collinearity Statistics
B
Std. Error
Beta
Tolerance
VIF
1
(Constant)
4.677
1.720
2.719
.007
enthusiasm for task
.318
.253
.074
1.254
.211
.936
1.069
age
.372
.072
.322
5.135
.000
.834
1.199
gender
-3.374
.589
-.342
-5.731
.000
.922
1.085
hand2
-.109
.620
-.011
-.176
.861
.895
1.118
dumgroup
.898
.567
.094
1.585
.114
.935
1.069
a. Dependent Variable: time10
From the above table, it can be understood that there is not too much multicolinearity between the variables because the values of tolerance and VIF are near to 1 which is a good indication (Cohen, 2003, pp. ...