For the June temperature data in Table A.3, a. Use a two-sample t test to investigate whether the average June temperatures in El Nino and non-El Nino years are significantly different. Assume that...

For the June temperature data in Table A.3,

a. Use a two-sample t test to investigate whether the average June temperatures in El Nino and non-El Nino years are significantly different. Assume that the variances are unequal and that the Gaussian distribution is an adequate approximation to the distribution of the test statistic.

b. Construct a 95% confidence interval for the difference in average June temperature between El Nino and non-El Nino years.