In: Statistics and Probability
You may need to use the appropriate technology to answer this question.
Consider the following sample of production volumes and total cost data for a manufacturing operation.
Production
Volume (units) |
Total Cost ($) |
---|---|
400 | 4,100 |
450 | 5,000 |
550 | 5,500 |
600 | 5,900 |
700 | 6,500 |
750 | 7,000 |
This data was used to develop an estimated regression equation,
ŷ = 1,342.67 + 7.52x,
relating production volume and cost for a particular manufacturing operation. Use
α = 0.05
to test whether the production volume is significantly related to the total cost. (Use the F test.)
State the null and alternative hypotheses.
H0: β1 ≠ 0
Ha: β1 =
0H0: β1 ≥ 0
Ha: β1 <
0 H0:
β0 ≠ 0
Ha: β0 =
0H0: β0 = 0
Ha: β0 ≠
0H0: β1 = 0
Ha: β1 ≠ 0
Set up the ANOVA table. (Round your p-value to three decimal places and all other values to two decimal places.)
Source of Variation |
Sum of Squares |
Degrees of Freedom |
Mean Square |
F | p-value |
---|---|---|---|---|---|
Regression | |||||
Error | |||||
Total |
Find the value of the test statistic. (Round your answer to two decimal places.)
Find the p-value. (Round your answer to three decimal places.)
p-value =
What is your conclusion?
Do not reject H0. We cannot conclude that the relationship between production volume and total cost is significant.
Reject H0. We cannot conclude that the relationship between production volume and total cost is significant.
Reject H0. We conclude that the relationship between production volume and total cost is significant.
Do not reject H0. We conclude that the relationship between production volume and total cost is significant.
Solution) :
Here,
Production Volume is independent variable(X)
Total cost is dependent variable(Y) .
Enter data in SPSS software as given below:
In variable view:
Production Volume as (scale) measure.
Total cost as (scale) measure.
In variable view:
Enter the data for both columns
To get the entered data in output :
Steps= analyse --- reports ---case summaries ---select both variable in variables column---ok
Production_Volume |
Total_Cost |
|
1 |
400 |
4100 |
2 |
450 |
5000 |
3 |
550 |
5500 |
4 |
600 |
5900 |
5 |
700 |
6500 |
6 |
750 |
7000 |
To perform simple regression in SPSS :
Steps : Analyse ---Regression---Linear---Dependent(Total cost)---Independent(Production volume)---method(enter)---Ok
Model Summary |
||||
Model |
R |
R Square |
Adjusted R Square |
Std. Error of the Estimate |
1 |
.986a |
.972 |
.965 |
194.765 |
a. Predictors: (Constant), Production_Volume |
R-square =0.972
Which means there is approximately 97.2% variability in Dependent variable(Total Cost) is explained by Independent Variable(Production Volume).
Coefficientsa |
||||||
Model |
Unstandardized Coefficients |
Standardized Coefficients |
t |
Sig. |
||
B |
Std. Error |
Beta |
||||
1 |
(Constant) |
1342.667 |
374.300 |
3.587 |
.023 |
|
Production_Volume |
7.520 |
.636 |
.986 |
11.822 |
.000 |
|
a. Dependent Variable: Total_Cost |
Here, from the above coefficient table ,we have
Intercept (β0) = 1342.67
Slope (β1) = 7.52
The Regression Equation is :
Ŷ = β0+β1X
=1342.67+7.52*X
Now,State the null and alternative hypotheses.
H0: β1 = 0
there is not significant relationship between production volume and
total cost.
Ha: β1 ≠
0 there is significant relationship between
production volume and total cost.
ANOVAa |
||||||
Model |
Sum of Squares |
df |
Mean Square |
F |
Sig. |
|
1 |
Regression |
5301600.00 |
1 |
5301600.00 |
139.76 |
.000b |
Residual |
151733.33 |
4 |
37933.33 |
|||
Total |
5453333.33 |
5 |
||||
a. Dependent Variable: Total_Cost |
||||||
b. Predictors: (Constant), Production_Volume |
Test statistic Value ,F=139.76
p-value =0.000<0.05 ,which means that regression is significant at 5% level of significance.
Conclusion: since p value is less than 0.05
. Reject H0. We conclude that the relationship between production volume and total cost is significant.