Find a confidence interval of the specified level for the difference in proportion of deep pits for each of the following values for humidity and pairs of durations.

a. \(40 \%\) humidity: Difference between proportions of deep pits at four weeks and 26 weeks, 95\% confidence

b. \(40 \%\) humidity: Difference between proportions of deep pits at 26 weeks and 52 weeks, \(99 \%\) confidence

c. \(75 \%\) humidity: Difference between proportions of deep pits at four weeks and 26 weeks, \(90 \%\) confidence

d. 75\% humidity: Difference between proportions of deep pits at 26 weeks and 52 weeks, \(98 \%\) confidence