4To help consumers assess the risks they are taking, the Food and Drug Administration (FDA) publishes the amount of nicotine found in all commercial brands of cigarettes. A new cigarette has recently been marketed. The FDA tests on this cigarette gave a mean nicotine content of 26.10 milligrams and standard deviation of 2.30 milligrams for a sample of n = 9 cigarettes.

Assuming that the amount of nicotine in a cigarette follows an approximately normal distribution, construct a 95% confidence interval for the mean nicotine content of this brand of cigarette.

We are standardisingx

withs

n

so we will need to use the t distribution to calculate t* (rather than using the Standard Normal distribution to calculate z*).

Select one:

26.10 1.768

26.10 1.734

26.10 1.426

26.10 2.110