Histidine excretion. Exercise 12.4 introduced data in which 24-hour histidine excretion was compared in men and women on protein-restricted diets. Table 12.11 lists mean and standard deviations from this dataset.

a) Calculate the standard error of the mean difference without assuming equal variances.

b) A computer program calculates for these data. Based on this df, calculate a 95% confidence interval for mu1-mu2.

c) Carry out a hypothesis test of whether mean histidine excretion differs between men and women on protein-restricted diets.

Hypotheses in words and symbols:

Assumptions:

Results: n1=5,mu1 = 219.4mg,

n2=6, mu2 = 163.8mg,

mu_d = 55.6 mg, t = 2.49, df = 9

P-value (two-sided) =????

Our test statistic is

Interpretation: