Question

In order to estimate the difference between the average Miles per Gallon of two different models of automobiles, samples are taken, and the following information is collected. Model A Model B Sample Size 50 55 Sample Mean 32 35 Sample Variance 9 10 a) At 95% confidence develop an interval estimate for the difference between the average Miles per Gallon for the two models. b) Is there conclusive evidence to indicate that one model gets a higher MPG than the other

Answer 1

Answer:

At 95% confidence limits for the true difference between the  average Miles per Gallon for the two models is -1.8210  to  4.1789

Yes 95 % confidence means  that there's conclusive evidence to indicate that one model gets a higher MPG than the other.

Step-by-step explanation:

                              Model A              Model B

Sample Size              50                          55

Sample Mean  x`         32                           35

Sample Variance  s²    9                            10

At 95 % confidence limits are given by

x1`-x2` ± 1.96 $\sqrt{\frac{s^{2} }{n1} +\frac{s^{2}}{n2} }$

Putting the values

32-35  ± 1.96  $\sqrt\frac{9}{50}+\frac{10}{55}$        ( the variance is the square of  standard deviation)

-3 ± 1.96 $\sqrt{ \frac{495+500}{2750}$

-3 ± 1.96( 0.6015)

-3 ± 1.17896

-1.8210; 4.1789

Thus the 95% confidence limits for the true difference between the  average Miles per Gallon for the two models is -1.8210  to  4.1789.

Yes 95 % confidence means  that there's conclusive evidence to indicate that one model gets a higher MPG than the other.