Exercise 39 considered possible changes in the numbers of tropical cyclones that have grown large enough to be officially named.

In exercise It has been suggested that global climate change may be affecting the frequency of tropical storms. The data here show the number of tropical cyclones (including hurricanes) assigned official names by the National Hurricane Center. Is there evidence of a change?

Regardless of the number of storms, has the fraction of named storms that grew to hurricane strength changed? Here are those fractions for the same periods as those considered in the previous exercise.

a) Write the null and alternative hypotheses.
b) Are the conditions for hypothesis testing satisfied?
c) If so, test the hypothesis.

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1995-2001 2002-2012 19, 13,7, 14, 12,14,152, 16, 15, 27,9, 15, 16, 9, 19, 18, 19 1995-2001 2002-2012 0.579, 0.692, 0.429,0.714, 0.333,0.438,0.600, 0.556, 0.556, 0.667, 0.571,0.600 0.400, 0.500,0.333, 0.632,0.333,0.526