Question

 

A study is run comparing HDL cholesterol levels between persons who exercise regularly and those who do not. The data are shown below in Table 1.

Table: Mean HDL Cholesterol Levels by Regular Exercise

Group	n	Mean	Std Dev
No Regular Exercise	8	55	11.9
Regular Exercise	8	45	12.1

Is the mean HDL cholesterol levels in the group with “no regular exercise” statistically greater than those who exercise regularly at an a=.05? S_p=12

Generate a 95% confidence interval for the mean difference in HDL cholesterol levels between the two groups. S_p=12

 

 

 

Interpret this 95% CI (HINT: What does it mean?)

Answer 1

1)

from above as test statistic 1.667 is not higher then crtiical value we can not reject null hypotheiss

we do nt have evidence at 0.05 level to conclude that mean HDL cholesterol levels in the group with “no regular exercise” statistically greater than those who exercise regularly

2)

for 95% confidence :

point estimate of mean difference=			x1-x2	=	10.000
for 95 % CI & 14 df value of t=				=	2.1450
margin of error E=t*std error                            =					12.870
lower confidence bound=mean difference-margin of error =					-2.87
Upper confidence bound=mean differnce +margin of error=					22.87

95% confidence interval for the mean difference =-2.87 ; 22.87

for above 95% CI refers of having 95% confidence that above interval contains population mean difference of  HDL cholesterol levels between  group with “no regular exercise” and group with exercise regularly