Test whether the 1951–1980 July precipitation data in Table 4.8 might have been drawn from the same distribution as the 1951–1980 January precipitation comprising part of Table A.2, using a likelihood...

Test whether the 1951–1980 July precipitation data in Table 4.8 might have been drawn from the same distribution as the 1951–1980 January precipitation comprising part of Table A.2, using a likelihood ratio test, assuming gamma distributions.

Use the Wilcoxon-Mann-Whitney test to investigate whether the magnitudes of the pressure data in Table A.3 are lower in El Nino years,

a. Using the exact one-tailed critical values 18, 14, 11, and 8 for tests at the 5%, 2.5%, 1%, and 0.5% levels, respectively, for the smaller of U₁
and U₂.

b. Using the Gaussian approximation to the sampling distribution of U.