Question: Reproduction of bacteria-infected spider mites. Zoologists in Japan investigated the reproductive traits of spider mites with a bacteria infection (Heredity, January 2007). Male and female pairs of infected spider mites were mated in a laboratory, and the number of eggs produced by each female recorded. Summary statistics for several samples are provided in the accompanying table. Note that in some samples, one or both infected spider mites were treated with an antibiotic prior to mating.

(a) For each female/male pair type, construct and interpret a 90% confidence interval for the population mean number of eggs produced by the female spider mite.

(b) Identify the female/male pair type that appears to produce the highest mean number of eggs.

Female/Male Paris           Sample Size         Mean # of Eggs            Standard Deviation

Both untreated                   29                       20.9                             3.34

Male treated                      23                       20.3                             3.50

Female treated                   18                       22.9                             4.37

Both treated                      21                       18.6                              2.11