Ch 11 Q 10 As part of the Womens Health Trial one grou pof w

Ch. 11 Q 10

As part of the Women\'s Health Trial, one grou pof women were encouraged to adopt a low-fat diet while a second group received no dietary counseling. A year later, the women in the intervention group had successfully maintained their diets. At that time, a study was undertaken to determine whether their husbands also had a reduced level of fat intake.

B) Formally test the null hypothesis that the two groups of men have the same mean dietary fat intake using a two-sided test. What do you conclude?

C) Construct a 95% Confidence Inerval for the true difference in population means.

Solution

H0: mu1 =mu2

Ha: mu1 not equal to mu2

The mean of Group One minus Group Two equals -14.700

standard error of difference = 44.436

t = 0.3308
  df = 302

95% confidence interval of this difference: From -102.144 to 72.744

The two-tailed P value equals 0.7410
  By conventional criteria, this difference is considered to be not statistically significant.

Hence accept null hypothesis that two means are equal.

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D)

The mean of Group One minus Group Two equals -13.000
  95% confidence interval of this difference: From -204.865 to 178.865


  t = 0.1333
  df = 302
  standard error of difference = 97.500

The two-tailed P value equals 0.8940
  By conventional criteria, this difference is considered to be not statistically significant.

Hence accept null hypothesis.