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other:inspect3d:tutorials:analysis_of_baseball_hitters [2025/01/10 20:47] – wikisysopother:inspect3d:tutorials:analysis_of_baseball_hitters [2025/01/10 20:49] (current) – wikisysop
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 Variance explained is the first graph displayed after running a PCA, and displays the variance explained by each principal component as well as the cumulative variance of each principal component. We can see that 90.0% of the variance can be explained by the first five principal components. Generally you want to increase the number of PCs until they explain 95% of the variance, but for this data set 7 PCs are needed to reach that variance and we don't want to start overfitting or capturing too much noise, so the number of PCs will be left at five. Variance explained is the first graph displayed after running a PCA, and displays the variance explained by each principal component as well as the cumulative variance of each principal component. We can see that 90.0% of the variance can be explained by the first five principal components. Generally you want to increase the number of PCs until they explain 95% of the variance, but for this data set 7 PCs are needed to reach that variance and we don't want to start overfitting or capturing too much noise, so the number of PCs will be left at five.
  
-{{:HIGHSCOOL_variance_explained.jpg?800}}+{{:HIGHSCOOL_variance_explained.jpg}}
  
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 When looking at the group scores the goal is to be able to confidently classify subjects as either being college or high school hitters. Analyzing this graph shows that the standard errors of all five PCs do not overlap, suggesting that all 5 PCs can differentiate between the groups. We can see from variance explained that PC1 accounts for the most overall variation at 38.9%, but since PC2 and PC5 are showing the most significant differences for each group, due to the group scores not overlapping and not crossing over zero they will be the focus of the remaining analysis. When looking at the group scores the goal is to be able to confidently classify subjects as either being college or high school hitters. Analyzing this graph shows that the standard errors of all five PCs do not overlap, suggesting that all 5 PCs can differentiate between the groups. We can see from variance explained that PC1 accounts for the most overall variation at 38.9%, but since PC2 and PC5 are showing the most significant differences for each group, due to the group scores not overlapping and not crossing over zero they will be the focus of the remaining analysis.
  
-{{:HIGHSCHOOL_Group_Score.jpg?800}}+{{:HIGHSCHOOL_Group_Score.jpg}}
  
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 We can take a closer look at PC2 and PC5 to see why these principal components may be showing the most significant differences. Looking at the mean signal trace of the college and high school subjects pelvic internal/external rotation, we can see that the majority of the difference in their swings are at the peak of their pelvic velocity, and also interestingly the high school players have more internal rotation before and at the end of there swing which is represented in PC2. PC5 is less clear and harder to interpret, once again we can see that the high and low points around 80-90 on the x axis are showing the variability between the subjects peak pelvic angular velocity, and the large value around 40 seems to point out that there were more college players with an earlier swing, but the rest is hard to decipher. We can take a closer look at PC2 and PC5 to see why these principal components may be showing the most significant differences. Looking at the mean signal trace of the college and high school subjects pelvic internal/external rotation, we can see that the majority of the difference in their swings are at the peak of their pelvic velocity, and also interestingly the high school players have more internal rotation before and at the end of there swing which is represented in PC2. PC5 is less clear and harder to interpret, once again we can see that the high and low points around 80-90 on the x axis are showing the variability between the subjects peak pelvic angular velocity, and the large value around 40 seems to point out that there were more college players with an earlier swing, but the rest is hard to decipher.
  
-{{:PC2_baseball.jpg}}{{:PC5_baseball.jpg}}+{{:PC2_baseball.jpg?400}}{{:PC5_baseball.jpg?400}}
  
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other/inspect3d/tutorials/analysis_of_baseball_hitters.1736542052.txt.gz · Last modified: 2025/01/10 20:47 by wikisysop