Question

Data on the blood cholesterol levels of 6 rats give mean = 85, s= 12. A 95% confidence interval for the mean blood cholesterol of rats under this condition is
(a)72.4 to 97.6
(b)73.0 to 97.0
(c)75.4 to 94.6
(d)72.4 to 94.6

Answer 1

i thinks
The equation of this would be

true \ mean=mean \ +/- \ z\frac{s}{ \sqrt{n} }

The z-value for a 95% confidence level is equal to 1.96.

Then the lower limit would be:

85-1.96 \frac{12}{ \sqrt{6} }=75.398

And the higher limit would be:

85+1.96 \frac{12}{ \sqrt{6} }=94.60

Therefore, the answer is

c)75.4 to 94.6