Question: The National Institute of Health is studying the birth weight of babies born to mothers who smoke cigarettes. A sample of the weights of 12 babies is selected and the weights are listed below in pounds.

6.1 7.9 5.8 7.4 6.3 8.2 7.1 6.5 6.7 5.2 9.1 6.0

(a) Construct a stem-and-leaf plot for the data.

(b) Find the five-number summary for the data and use it to construct a box-and-whisker plot.

(c) Find the point estimates for the population mean and the population standard deviation.

(d) Construct a 98% confidence interval for the population mean.

(e) At a = 0.02 and using critical regions, test the claim that the birth weights of these babies are less than 7 pounds.

(f) Interpret your results.