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HOMERUNNER Math 120 – Elementray Statistics 1 Manju Poudel Professor: Dr. Prabha Betne Date: 05/22/05 Homerun distances in feet McGwire (1), Sosa (2), Bonds (3) McGwire (1998) Statistic Mean 418.51 95% Confidence Interval for Mean Sosa (1998) Bonds (2001) Std. Error Lower Bound Upper Bound 5% Trimmed Mean Median Variance Std. Deviation Minimum Maximum Range Interquartile Range Skewness Kurtosis Mean 95% Confidence Lower Bound Interval for Mean Upper Bound 5% Trimmed Mean Median Variance Std. Deviation Minimum Maximum Range Interquartile Range Skewness Kurtosis Mean 95% Confidence Lower Bound Interval for Mean Upper Bound 5% Trimmed Mean Median Variance Std. Deviation Minimum Maximum Range Interquartile Range Skewness Kurtosis 5.438 407.67 429.36 416.63 420.00 2069.732 45.494 340 550 210 70.00 .572 .146 404.85 .287 .566 4.394 396.07 413.62 403.62 410.00 1274.254 35.697 340 500 160 59.25 .361 -.123 403.67 .295 .582 3.586 396.52 410.82 404.48 410.00 938.696 30.638 320 488 168 40.00 -.408 .596 .281 .555 1. Quickly scanning the data given above, McGwire appears to be the best player compared to the other two. But when we give deeper examination of the data, final outcome can be completely different than what we judge roughly. If we take mean value only, mean value of McGwire’s homerun is higher than Sosa and Bonds. That means, he has made equal to or more than 50% runs 418.51 feet or higher. The difference between the mean distance covered by Sosa and Bonds is minimal. It is apparent that McGwire is ahead of the other two in average distance covered in all of the homeruns he made. The median value of his homeruns (420) is greater than the median values of the other two, which are exactly the same (410 each). While examining maximum distance covered in their homeruns, we find that McGwire is far ahead of the other two. There is only a12 foot difference in maximum distance covered by Sosa and Bonds. Compared to a 50-foot difference between maximum distance covered by McGwire and Sosa. The difference between distance covered by Sosa and Bonds is negligible. When we compare minimum distance covered by all three players, McGwire and Sosa have covered equal distance. Bonds have covered 20 foot less than the other two. Thus, while examining the figures given in above table, individually McGwire appears to be strongest of three players and Bonds appears to be the weakest one. Nevertheless, keeping in mind that the calculation of average is very sensitive to extreme values and noticing that McGwire’s maximum value (550) is 50 feet higher than Sosa’s (500) and 62 feet higher than Bonds’ (488) we cannot rely on this information alone. The median, on the other hand, being the same for Sosa and Bonds (410) is only 10 ft less than McGwire’s, which tell us that the center of the distances is not much different for all the players. 2. Examining all three histograms we can come to a conclusion that it is irrational to say that player who hits farther hits more homeruns. In this scenario, Bonds (73), who seems to be weaker in hitting farther than other two has made more homeruns than other two (McGwire 70 and Sosa 66). 3. Standard deviation means deviation in numeric trends from mean and median or average. When comparing standard deviation (McGwire: 45.494, Sosa: 35.697, Bonds: 30.638) bonds seems to be more consistent in hitting homerun than other two as standard deviation value in Bonds’ playing history is least (30.638) of all three. 4. A quartile is one of the four divisions of observations, which have been grouped into four equal-sized sets based on their statistical rank. So, Q1 should be mean of all data above mean and Q2 should be mean of all data below mean. In this problem, quartiles are not given but interruptible ranges (that could be calculated if Q1 and Q2 were available) are given. Thus, instead of compare quartiles, we can compare only IQR. The IQR is a measure of spread or dispersion. In our case, IQR of Bonds (40) is much less than of the McGwire (70) and Sosa (59.25). This also shows consistency in Bonds’ homerun hitting pattern. Sosa appears to be more consistent than McGwire. 5. Looking at histogram of all three players, we can find that McGwire’s histogram is more spread than other two. This shows that he hits long inconsistent long distances most frequently whilst Sosa hit 420 to 430 feet most frequently than others and Bonds hits 410 to 440 feet most frequently. It shows that Bonds makes more calculated hits that help him to hit homeruns. We could conclude that McGwire is a more unpredictable player, hit haphazard long distances capable of hitting less homeruns (less than 15) in more variable distances. Although he hit more long distances, he has less chances of hitting homeruns compared to Bonds. Histogram For PLAYER= McGwire (1998) 20 15 Frequency 10 5 Std. Dev = 45.49 Mean = 418.5 N = 70.00 0 330.0 370.0 350.0 410.0 390.0 450.0 430.0 Homerun distances in feet 490.0 470.0 530.0 510.0 550.0 Histogram For PLAYER= Sosa (1998) 20 Frequency 10 Std. Dev = 35.70 Mean = 404.8 N = 66.00 0 330.0 370.0 350.0 410.0 390.0 450.0 430.0 490.0 470.0 530.0 510.0 550.0 Homerun distances in feet Histogram For PLAYER= Bonds (2001) 30 Frequency 20 10 Std. Dev = 30.64 Mean = 403.7 N = 73.00 0 330.0 370.0 350.0 410.0 390.0 450.0 430.0 490.0 470.0 530.0 510.0 550.0 Homerun distances in feet 6. Comparing box plots we can concludes that standard deviation of Bonds’ hits is less than other two. He has fixed range of distance of hitting. That may give room for opponents for prediction that can case reduction of homeruns, though he is highest home runner. McGwire appears unpredictable as his standard deviation is high and Sosa remains between McGwire and Bonds in predictability of pattern of hitting long distance. 7. Based on statistical data given, we can conclude that Bonds is more consistent, predictable and capable of hitting more homeruns than others. McGwire is versatile, unpredictable and relatively good homerun hitter. Sosa is relatively consistent, predictable and above the average players. Looking at the number of homeruns McGwire hit, we can say that his unpredictability is probably the greatest strength of him whilst predictability and consistency are Bonds’ strength. 600 500 197 400 177 169 300 N= 70 66 73 McGw ire (1998) Sosa (1998) Bonds (2001) McGwire (1), Sosa (2), Bonds (3)