Answer :
To test whether the mean time needed to mix a batch of material is the same for machines produced by three manufacturers, we can use ANOVA (Analysis of Variance). Here is a step-by-step solution using the data provided:
Given data (mixing times in minutes):
```
Manufacturer 1: 15, 21, 19, 17
Manufacturer 2: 31, 29, 34, 30
Manufacturer 3: 21, 20, 24, 23
```
a. Use these data to test whether the population mean times for mixing a batch of material differ for the three manufacturers at [tex]\(\alpha = 0.05\)[/tex].
### 1. Calculate the Overall Mean
The overall mean is the average of all values from the three manufacturers combined.
### 2. Calculate the Treatment Means
- Mean of Manufacturer 1
- Mean of Manufacturer 2
- Mean of Manufacturer 3
### 3. Calculate the Sum of Squares Treatment (SST)
SST measures the variability due to the interaction between the groups (treatments).
### 4. Calculate the Sum of Squares Error (SSE)
SSE measures the variability within the groups.
### 5. Calculate the Mean Squares
- Mean Square Treatment (MST)
- Mean Square Error (MSE)
### 6. Calculate the F-statistic
The F-statistic is used to determine if the variability between the group means is more than would be expected by chance.
### 7. Determine the p-value
The p-value will help us decide whether to reject the null hypothesis.
### Given Results
Based on the calculations, we have:
- Sum of Squares, Treatment (SST): 354.67
- Sum of Squares, Error (SSE): 44.00
- Mean Squares, Treatment (MST): 177.33
- Mean Squares, Error (MSE): 4.89
- F-statistic: 36.27
- p-value: 0.00
### Conclusion
The p-value is very small (0.00), much smaller than the significance level [tex]\(\alpha = 0.05\)[/tex].
- Decision: Since the p-value is less than [tex]\(\alpha\)[/tex], we reject the null hypothesis.
- Conclusion: There is significant evidence to suggest that the population mean times for mixing a batch of material differ for the three manufacturers.
So, the final values are:
- Sum of Squares, Treatment: 354.67
- Sum of Squares, Error: 44.00
- Mean Squares, Treatment: 177.33
- Mean Squares, Error: 4.89
- F-statistic: 36.27
- p-value: 0.00
- Conclusion: There is a significant difference in the mean mixing times among the three manufacturers.
Given data (mixing times in minutes):
```
Manufacturer 1: 15, 21, 19, 17
Manufacturer 2: 31, 29, 34, 30
Manufacturer 3: 21, 20, 24, 23
```
a. Use these data to test whether the population mean times for mixing a batch of material differ for the three manufacturers at [tex]\(\alpha = 0.05\)[/tex].
### 1. Calculate the Overall Mean
The overall mean is the average of all values from the three manufacturers combined.
### 2. Calculate the Treatment Means
- Mean of Manufacturer 1
- Mean of Manufacturer 2
- Mean of Manufacturer 3
### 3. Calculate the Sum of Squares Treatment (SST)
SST measures the variability due to the interaction between the groups (treatments).
### 4. Calculate the Sum of Squares Error (SSE)
SSE measures the variability within the groups.
### 5. Calculate the Mean Squares
- Mean Square Treatment (MST)
- Mean Square Error (MSE)
### 6. Calculate the F-statistic
The F-statistic is used to determine if the variability between the group means is more than would be expected by chance.
### 7. Determine the p-value
The p-value will help us decide whether to reject the null hypothesis.
### Given Results
Based on the calculations, we have:
- Sum of Squares, Treatment (SST): 354.67
- Sum of Squares, Error (SSE): 44.00
- Mean Squares, Treatment (MST): 177.33
- Mean Squares, Error (MSE): 4.89
- F-statistic: 36.27
- p-value: 0.00
### Conclusion
The p-value is very small (0.00), much smaller than the significance level [tex]\(\alpha = 0.05\)[/tex].
- Decision: Since the p-value is less than [tex]\(\alpha\)[/tex], we reject the null hypothesis.
- Conclusion: There is significant evidence to suggest that the population mean times for mixing a batch of material differ for the three manufacturers.
So, the final values are:
- Sum of Squares, Treatment: 354.67
- Sum of Squares, Error: 44.00
- Mean Squares, Treatment: 177.33
- Mean Squares, Error: 4.89
- F-statistic: 36.27
- p-value: 0.00
- Conclusion: There is a significant difference in the mean mixing times among the three manufacturers.