In a certain year, there were 80 days with measurable snowfall in Denver and 63 days with measurable snowfall in Chicago. A meteorologist computes

(80 + 1)∕(365 + 2) = 0.22, (63 + 1)∕(365 + 2) =

0.17, and he proposes to compute a 95% confidence interval for the difference between the proportions of snowy days in the two cities as follows:

0.22 − 0.17 ± 1.96√(0.22)(0.78)

367 + (0.17)(0.83)

367 Is this a valid confidence interval? Explain?