A sample of 20 fruitfly (Drosophila melanogaster) larva were incubated at 37 °C for 30 minutes. It is theorized that such exposure to heat causes polytene chromosomes located in the salivary glands of the fly to unwind, creating puffs on the chromosome arm that are visible under a microscope. The following normal probabilityplot supports the use of a normal curve to model the distribution of puffs.50
The average number of puffs for the 20 observations was 4.30, with a standard deviation of 2.03.
(a) Construct a 95% confidence interval for 
.
(b) In the context of this problem, describe what 
represents. That is, the confidence interval from part (a) is a confidence interval for what quantity?
(c) The normal probability plot shows the dots lining up on horizontal bands. Is this sort of behavior surprising for this type of data? Explain.