Solution to Chapter 2 Internet Project

Data on the Internet
Note: In exercises 1 and 2 the data for the year 2000 is used. Exercise 1 Using the daily mean temperatures, compute the range and standard deviation in temperature for San Francisco in January 2000. Answer The mean daily temperatures for each of the days in January 2000 as compiled by the Weather Underground are 50.8 48.5 47.8 55.9 52.1 47.8 47.7 50.5 51.3 52.4 54.1 49.6 50.5 52.6 53.9 56.4 50.5 52.8 55.5 55.3 52.4 53.6 54.6 56.2 54.4 51.5 50.5 50.3 51.1 54.9 52.6 . For this data n = 31

∑ x = 1618.1 ∑ x 2 = 84653.61 so the mean and standard deviation are x= 1618.1 = 52.20 31 and s= 31(84653.61) − (1618.1) 2 = 2.54 . 31(30)

Exercise 2 The National Football League uses a long list of criteria to determine if a city is a candidate to host the Super Bowl. One such requirement is that the city either must have a domed (i.e. heated) football stadium or that the average temperature in January for the city must be 50o F or higher. San Francisco does not have a domed stadium. Based on the January 2000 data, would San Francisco satisfy this Super Bowl eligibility criterion? Answer Yes, since the average from Exercise 1 is 52.20. Exercise 3 Which graph below best represents the performance of Microsoft stock during the first four months of 2000? Answer Graph B shows the history of Microsoft stock prices over the indicated period. Note the data is graphed in the form it is provided on the Yahoo! finance site so that January 1 is on the right. Exercise 4 What is the range in price of Microsoft stock during the first four months of 2000? When did Microsoft stock reach its lowest closing price? When was the largest volume of stock traded? Answer The highest closing price, $116.56, occurred on January 1, 2000. The lowest closing price for this period was $66.63 on April 24, 2000, the same day the trading was greatest. The range for the four month period was $116.56 - $66.63 = $49.93. Exercise 5 Which player, Mark McGwire or Sammy Sosa, surpassed the record of 61 home runs first?

Solution to Chapter 2 Internet Project

Data on the Internet
Answer Reading the graph given in the project from left to right, one sees the graph for McGwire reaching a height of 62 before the graph for Sosa. Thus Mark McGwire was the first to break Roger Maris’ single season home run record. Exercise 6 Which player, Mark McGwire or Sammy Sosa, tends to hit longer home runs? Use statistics to argue your answer. Who had the largest range in home run depth? Answer The average distance of Mark McGwire’s home runs in 1998 was 422.4 feet while Sammy Sosa’s average distance was 407.5 feet. Also note that 21 of McGwire’s 70 home runs or 30% went over 450 feet. Only 12% of Sosa’s 66 home runs achieved that distance. Thus one could argue that Mark McGwire tends to hit longer home runs. McGwire exhibited the greatest range in home run distance (545 – 341 = 204 feet) to Sosa’s range of 500 – 340 = 160 feet.