Using the regression line, we can calculate:
1. If x = 0:
y = 3.473(0) - 155.317
y = -155.317
Therefore, if the students type zero words per minute, the regression line predicts they will make approximately -155 errors. Since you can't have negative errors, this doesn't make sense in this context.
2. For an increase of one word per minute typing speed:
The coefficient of x in the regression line is 3.473, so for an increase of one word per minute typing speed, the regression line predicts an increase of 3.473 errors.
3. If x = 50:
y = 3.473(50) - 155.317
y = 173.783
Therefore, if a student types at 50 words per minute, the regression line predicts they will make approximately 173.783 errors.
4. If x = 70:
y = 3.473(70) - 155.317
y = 177.983
Therefore, if a student types at 70 words per minute, the regression line predicts they will make approximately 177.983 errors.
Based on the regression line, it appears that as typing speed increases, the number of errors also increases, which does not support Mr. Moore's claim.