Question

A special diet is intended to reduce systolic blood pressure. If the diet is effective, the target is to

have the average systolic blood pressure of this group be below 150. After six months on the diet an SRS of 28 patients with high blood pressure had an average cholesterol of X= 143 with a standard deviation of s= 21. Is this sufficient evidence that the diet is effective in meeting the target? Assume the distribution of the cholesterol for patients in this group is approximately Normal with mean u.

The appropriate degrees of freedom using the conservative method #2

A.27 B. 28 C. 20 D. 149

Answer 1

we have to test that if the systolic blood pressure is less than 150 or not hence

sample size=n=28

we have sample mean =x=143

sample SD=S=21

now test statistics is given by

The appropriate degrees of freedom =n-1=28-1=27

Hence option (A) is correct

now test is left tailed so

P-Value =P(t<-1.76)=0.045

Since P Value is less than level of significance (0.05) Hence we reject H0 Hence there is enough evidence to conclude that average systolic blood pressure is less than 150