Do various occupational groups differ in their diets? A British study of this qu

Question

Do various occupational groups differ in their diets? A British study of this question compared 91 drivers and 62 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.

(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.)

Explanation / Answer

e) Degree of freedo, df = (s12/n1 + s22/n2)2 / { [ (s12 / n1)2 / (n1 - 1) ] + [ (s22 / n2)2 / (n2 - 1) ] } where 1 is for conductor and 2 is for driver

Since the standard error is provided, find the std. dev. by using the formula, s = se * sqrt(n)
s1 = 0.14*sqrt(62) = 1.10236
s2 = 0.1*sqrt(91) = 0.953939

df = 118.2592 = 118

tcrit = +/- 2.618

c - d +/- tcrit * sqrt(se12 + se22) = (0.38 - 0.27) +/- 2.618*sqrt(0.142 + 0.12) = (-0.340, 0.560)

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.