10.19 Is the number of tornadoes increasing? The Storm Prediction Center of the National Oceanic and Atmospheric Administration maintains a database of tornadoes, floods, and other weather phenomena. Table 10.1 summarizes the annual number of tornadoes ir the United States between 1953 and 2014. O TWISTER (a) Make a plot of the total number of tornadoes by year. Does a linear trend over years appear reasonable? Are there any outliers or unusual patterns? Explain your answer. Number of Tornadoes (1) 400 600 800 1200 1600 O 1960 1970 0 0 O 00 8 1980 o 8 O Year O Graph 8 O O 1990 2000 o . o 0 2010 000 Number of Tornadoes (2) 400 600 800 1200 1600 O 1960 O O 1970 00 o O 00 O 1980 o O Year Graph OO o 8 o 1990 2000 O o O o O O 2010 000 O Call: Im (formula - Tornadoes - Year) Residuals: Min 10 Median 30 Max - 443.57 -122.23 -8.01 109.18 613.78 Coefficients: Estimate Std. Error t value Pr(>01) (Intercept) -24517.13 2836.43 -8.644 3.94e-12 *** Year 12.84 1.438.975 1.09e-12 *** Signif. codes: O****' 0.001 ***+ 0.01 **' 0.05 '' 0.1'' Residual standard error: 201.5 on 60 degrees of freedom Multiple R-squared: 0.5731, Adjusted R-squared: 0.566 F-statistic: 80.56 on 1 and 60 DF, p-value: 1.086e-12