Download this page in PDF formatIs there a difference between amount in bag of different production day?
H0: There is NO difference between amount in bag of different production day
H1: There is a difference between amount in bag of different production day
1. Variables
Production day(day, Nominal)/Amount in a bag(amount, Scale)
![wps_clip_image-686[4]](http://worldtree.net/wp-content/uploads/2012/01/wps_clip_image-6864.png "wps_clip_image-686[4]")
2. Make error bar
Graphs->Legacy Dialogs->Error bar
![wps_clip_image-20187[4]](http://worldtree.net/wp-content/uploads/2012/01/wps_clip_image-201874.png "wps_clip_image-20187[4]")
Select Simple and Define
![wps_clip_image-16422[4]](http://worldtree.net/wp-content/uploads/2012/01/wps_clip_image-164224.png "wps_clip_image-16422[4]")
Variable= “Amount in a bag [amount]”
Category Axis=”Production day [day]”
![wps_clip_image-2948[4]](http://worldtree.net/wp-content/uploads/2012/01/wps_clip_image-29484.png "wps_clip_image-2948[4]")
3. One-Way ANOVA
Analyze -> Compare means -> One-Way ANOVA
![wps_clip_image-10653[4]](http://worldtree.net/wp-content/uploads/2012/01/wps_clip_image-106534.png "wps_clip_image-10653[4]")
Dependent List= Amount in a bag
Factor= Production day
![wps_clip_image-29925[4]](http://worldtree.net/wp-content/uploads/2012/01/wps_clip_image-299254.png "wps_clip_image-29925[4]")
4. Post Hoc (Bonferroni)
Purpose: To found out which group shows the difference(s)
Post Hoc test is ONLY required if there is a difference (or there are differences)
Click “Post Hoc” -> Bonferroni and select a sufficient significance level
![wps_clip_image-28609[4]](http://worldtree.net/wp-content/uploads/2012/01/wps_clip_image-286094.png "wps_clip_image-28609[4]")
![wps_clip_image-16582[4]](http://worldtree.net/wp-content/uploads/2012/01/wps_clip_image-165824.png "wps_clip_image-16582[4]")
Because p-value (sig) is lower than 0.05, therefore, the conclusion is:
There are differences between amount in bag of different production day (F=8.799,p=0.001).
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ANOVA |
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Amount in a bag |
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Sum of Squares |
df |
Mean Square |
F |
Sig. |
|
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Between Groups |
1133.067 |
2 |
566.533 |
8.799 |
.001 |
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Within Groups |
1738.400 |
27 |
64.385 |
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Total |
2871.467 |
29 |
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Moreover, According to the Post-Hoc test, the conclusion is:
There is a difference between amount in bag of Monday and Tuesday (p=0.001).
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Multiple Comparisons |
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Amount in a bag Bonferroni |
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(I) Production day |
(J) Production day |
Mean Difference (I-J) |
Std. Error |
Sig. |
95% Confidence Interval |
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|
Lower Bound |
Upper Bound |
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Monday |
Tuesday |
-8.600 |
3.588 |
.071 |
-17.76 |
.56 |
|
Wednesday |
-15.000* |
3.588 |
.001 |
-24.16 |
-5.84 |
|
|
Tuesday |
Monday |
8.600 |
3.588 |
.071 |
-.56 |
17.76 |
|
Wednesday |
-6.400 |
3.588 |
.257 |
-15.56 |
2.76 |
|
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Wednesday |
Monday |
15.000* |
3.588 |
.001 |
5.84 |
24.16 |
|
Tuesday |
6.400 |
3.588 |
.257 |
-2.76 |
15.56 |
|
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*. The mean difference is significant at the 0.05 level.
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