Question: The effectiveness on treating respiratory infections with herbal remedies was studied. “days of fever” was used to measure effects. Among 233 children treated with herbal remedies, the mean number of days with fever was 0.36 with a standard deviation of 1.53 days. Among 293 children given a placebo the mean was 0.77 with a standard deviation of 1.14 days. Don’t assume the population’s standard deviations are equal.

a) H₀: μ 1 = μ 2 versus H₁: μ 1< μ 2

b) H₀: μ 1 = μ 2 versus H₁: μ 1> μ 2

c) H₀: μ 1 = μ 2 versus H₁: μ 1 not equal to μ 2