Population Mean Inference

Data Summary

Variable	Sample Size	Mean	Sample Std Dev
Domestic MPG	35	33	10
Import MPG	47	34	9

Test of Hypothesis: t-Test
Domestic MPG - Import MPG

Alternative Hypothesis H_a: Difference of means 'Domestic MPG - Import MPG' is less than 0
5% lower critical value in units of data = -3.568353
Unequal population variances was assumed.

Difference of Means	Std Error	Obs t Stat	DF	5% t-Lower Critical	P-value
-1	2.14022	-0.467241	68.8674	-1.66728	0.320901

Test is not significant at 5% level.

P-value Graph: t-Test

Null density (in units of data): Student t; mean = 0, scale = 2.1402, df = 68.867
Alternative Hypothesis H_a: Difference of means 'Domestic MPG - Import MPG' is less than 0
Assumed unequal population variances

The title of the graph is P-value Graph: t-Test , The graph shows the distribution of Diff. of Sample Means , Obs Diff. of Sample Means = -1 , P-Value = 0.3209

Test of Hypothesis: z-Test
Domestic MPG - Import MPG

Alternative Hypothesis H_a: Difference of means 'Domestic MPG - Import MPG' is less than 0
5% lower critical value in units of data = -3.520351

Difference of Means	Std Error	Obs z Stat	5% z-Lower Critical	P-Value
-1	2.14022	-0.467241	-1.64485	0.320164

Test is not significant at 5% level.

P-value Graph: z-Test

Null density (in units of data): Normal; mean = 0 , sd = 2.1402
Alternative Hypothesis H_a: Difference of means 'Domestic MPG - Import MPG' is less than 0

The title of the graph is P-value Graph: z-Test , The graph shows the distribution of Diff. of Sample Means , Obs Diff. of Sample Means = -1 , P-Value = 0.32016