Question

Do various occupational groups differ in their diets? A British study of this question compared 88 drivers and 59 conductors of London double-decker buses. The conductors' jobs require more physical activity. The article reporting the study gives the data as "Mean daily consumption ± (se)." Some of the study results appear below.

	Drivers	Conductors
Total calories	2824 ± 42	2843 ± 47
Alcohol (grams)	0.21 ± 0.04	0.4 ± 0.1

What justifies the use of the pooled two-sample t test?

____The similarity of the sample means suggests that the population standard deviations are likely to be different.

____The similarity of the sample means suggests that the population standard deviations are likely to be similar.    

____The similarity of the sample standard deviations suggests that the population standard deviations are likely to be different.

____The similarity of the sample standard deviations suggests that the population standard deviations are likely to be similar.

Is there significant evidence at the 5% level that conductors consume more calories per day than do drivers? Use the pooled two-sample t test to obtain the P-value. (Give answers to 3 decimal places.)

t =
df =
P-value =

Answer 1