The mean age when smokers first start is 13 years old with a population standard deviation of 2 years. A researcher thinks that smoking age has significantly changed since the invention of...

The mean age when smokers first start is 13 years old with a population standard deviation of 2 years. A researcher thinks that smoking age has significantly changed since the invention of ENDS—electronic nicotine delivery systems. A survey of smokers of this generation was done to see if the mean age has changed. The sample of 33 smokers found that their mean starting age was 12.4 years old. Do the data support the claim at the 5% significance level?

What are the correct hypotheses?

H₀:                    years


H₁:                    years

Based on the hypotheses, find the following:

Test Statistic z =  (Round to 4 decimal places.)


Critical Values =±±  (Round to 2 decimal places.)

Based on the above we choose to

The correct summary would be:       that the mean age smokers first start is different than 13.