Two microprocessors are compared on a sample of six benchmark codes to determine whether there is a difference in speed. The times (in seconds) used by each processor on each code are given in the following table. Code 4 6 Processor A 27.2 18.1 27.2 19.7 24.5 22.1 Processor B 24.1 19.3 26.8 20.1 27.6 29.8 Can you conclude that the mean speeds of the two processors differ?

To test whether the mean time needed to mix a batch of material is the same for machines produced by three manufacturers, the Jacobs Chemical Company obtained the following data on the time (in minutes) needed to mix the material.   Manufacturer   1 2 3     20 30 15     26 28 14     24 33 18     22 29 17

Refer to the data presented in Exercise 2.86. Note that there were 50% more accidents in the 25 to less than 30 age group than in the 20 to less than 25 age group. Does this suggest that the older group of drivers in this city is more accident- prone than the younger group? What other explanation might account for the difference in accident rates?

We asked UST employees to tell us how many megabytes of memory (RAM) they have on their computer. WWe would like to test to see if the mean amount of memory is the same for three different academic departments. We have the memory amounts for six faculty members' machines in the three departments shown below. Dept. 1 Dept. 2 Dept. 3 1 2048 4096 4096 2 2048 2048 4096 3. 2048 2048 8192 computer 4 2048 4096 8192 2048 2048 4096 6. 2048 8192 4096 Here is the ANOVA table: Analysis of Variance Source DF Adj SS Adj MS F-Value P-Value Factor 34952533 17476267 XXX 0.020 Error XX 51030699 3402047 Total XX 85983232 Calculate the value of the F test statistic and enter here:

The National Football League (NFL) records a variety of performance data for individuals and teams. To investigate the importance of passing on the percentage of games won by a team, the following data show the average number of passing yards per attempt (Yds/Att) and the percentage of games won (WinPct) for a random sample of 10 NFL teams for the 2011 season (NFL website). Team Yds/Att WinPct 5.7 26 Arizona Cardinals Atlanta Falcons Carolina Panthers 7.6 67 7.3 52 6.9 51 Chicago Bears Dallas Cowboys 5.1 17 8.6 82 New England Patriots Philadelphia Eagles Seattle Seahawks 5.3 21 6.6 41 St. Louis Rams 6.5 41 Tampa Bay Buccaneers. 6.1 38 a. Choose the correct a scatter diagram with the number of passing yards per attempt on the horizontal axis and the percentage of games won on the vertical axis. B. A. WinPct WinPct 80 DD J F1 70- 60- 50+ -40- 30 20- F2 80 F3 000 000 F4 F5 80- -70 60- 50- 40- 30- 20- S F6 ● - F7 DII F8 F9 F10 () F11 <))) F12 A