Question

Do various occupational groups differ in their diets? A British study of this question compared 89 drivers and 66 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 2827 ± 14 2845 ± 15 Alcohol (grams) 0.27 ± 0.07 0.37 ± 0.12

(a) Give x and s for each of the four sets of measurements. (Give answers accurate to 3 decimal places.)

Drivers Total Calories: x = 2827 s = 132.076

Drivers Alcohol: x = s =

Conductors Total Calories: x = s =

Conductors Alcohol: x = s =

(b) Is there significant evidence at the 5% level that conductors consume more calories per day than do drivers? Use the conservative two-sample t method to find the t-statistic, and the degrees of freedom. (Round your answer for t to three decimal places.)

t =

df =

(c) How significant is the observed difference in mean alcohol consumption? Use the conservative two-sample t method to obtain the t-statistic. (Round your answer to three decimal places.) t =   

(d) Give a 95% confidence interval for the mean daily alcohol consumption of London double-decker bus conductors. (Round your answers to three decimal places.)

( )

(e) Give a 99% confidence interval for the difference in mean daily alcohol consumption for drivers and conductors. (conductors minus drivers. Round your answers to three decimal places.) ( )

Answer 1