When people smoke, the nicotine they absorb is converted to cotinine, which can be measured. A sample of 40 smokers has a mean cotinine level of 175 with a standard deviation is known to be 119.5, find a 90% confidence interval estimate of the mean cotinine level of all smokers.
answer: 140.7 < µ < 204.3
Choose the correct interpretation of the confidence interval for the mean cotinine level found above.
a.90% of the 40 data values lie between the lower and upper limits of the confidence interval.
b.There is a 90% chance that the cotinine level is equal to 172.5.
c.If we repeated this analysis 100 times, 90 of the intervals created would include the true mean cotinine level.
d.The probability that the mean cotinine level is 172.5 is 90%.