Hurricane Katrina hit New Orleans on August 29, 2005. The National Weather Service Forecast Office maintains online archives of climate data for all U.S. cities and areas. These archives allow us to find out, for example, how the rainfall in New Orleans that August compared to that in the other months of 2005. The table below shows the National Weather Service data (rainfall in inches) for New Orleans in 2005.

a. Calculate the z score for August, the month in which Hurricane Katrina hit.

b. What is the percentile for the rainfall in August? Does this surprise you? Explain.

c. When results surprise us, it is worthwhile to examine individual data points more closely or even to go beyond the data. The daily climate data as listed by this source for August 2005 shows the code €œM€ next to August 29, 30, and 31 for all climate statistics. The code says: €œ[REMARKS] ALL DATA MISSING AUGUST 29, 30, AND 31 DUE TO HURRICANE KATRINA.€ Pretend you were hired as a consultant to determine the percentile for that August. Write a brief paragraph for your report, explaining why the data you generated are likely to be inaccurate.

d. What raw scores mark the cutoff for the top and bottom 10% for these data? Based on these scores, which months had extreme data for 2005? Why should we not trust these data? 

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January 4.41 February 8.24 March 4.69 April 3.31 May 4.07 June 2.52 July 10.65 August 3.77 September 4.07 October 0.04 November 0.75 December 3.32