Question

6. To prevent E. coli, meat should be cooked to an internal temperature of at least 160°F. However, different meat patties cooked for the same amount of time will have different final internal temperatures because of variations in the patties and variations in burner temperatures. A regional hamburger chain plans to replace its current burners with one of two new digitally controlled models. If there is a significant difference in the variance of the two models, the chain will select the model with the smaller variance in the final internal meat temperature. The chain's purchasing directors have arranged to randomly sample 11 patties cooked by burner model 1 and 13 cooked by burner model 2. The final internal temperature of the patties cooked on each burner are in cells F117 to G130 on the answers sheet. Perform a hypothesis test at the 10% significance level to see whether there is a significant difference between the variances of the two burner models.

DATA:

	Model 1	Model 2
1	180.0	178.6
2	181.5	182.3
3	178.9	177.5
4	176.4	180.6
5	180.7	178.3
6	181.0	180.7
7	180.3	181.4
8	184.6	180.5
9	185.6	179.6
10	179.7	178.2
11	178.9	182.0
12		181.5
13		180.8

ANSWER FORMAT:

Define H0 :
Define H1 :
Test statistic
Critical value of test statistic
Decision rule
Calculated value of test statistic
Reject or fail to reject H0?
Can we conclude the population variances are equal?

Answer 1