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

The equation of this would be



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

Then the lower limit would be:



And the higher limit would be:



Therefore, the answer is

c)75.4 to 94.6

I hope I was able to explain it clearly. Have a good day :)