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. The Storm Prediction Center of the National Oceanic and Atmospheric Administration maintains a list of tornadoes, floods, and other weather phenomena. Table 10.8 summarizes the annual number of tornadoes in the United States between 1953 and 2008.19 DATADATA

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 (a) Make a plot of the total number of tornadoes by year. Is there a linear trend over time? Are there any outliers or unusual patterns? Explain your answer.

(b) Run the simple linear regression and summarize the results, making sure to construct a 95% confidence interval for the average annual increase in the number of tornadoes.

(c) Obtain the residuals and plot them versus year. Is there anything unusual in the plot?

(d) Are the residuals Normal? Justify your answer.