The data set “Tornadoes_2017” located at www.pearsonhighered.com/sullivanstats contains a variety of variables that were measured for all tornadoes in the United States in 2017.
(a) Compute the population mean length of a tornado in the United States in 2017.
(b) The data file 10_3_35b represents the length of a random sample of 40 tornadoes in Texas in 2017. Draw a boxplot of the length data. Are there any outliers? Comment on the shape of the distribution.
(c) Explain why a large sample size is necessary to use Student’s t-distribution to test a hypothesis about a population mean.
(d) Does the sample data suggest tornadoes have a different length in Texas?
(e) The data file 10_3_35e represents an independent random sample of 40 tornadoes in Texas in 2017. Does this sample data suggest tornadoes have a different length in Texas?
(f) Compare the results of parts (d) and (e). Explain why the conclusions may differ.