Part A
Answer: 8
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The slope is 8 because it is the number in front of the x in y = 8x+40, which is the regression line. The regression line is in the form y = mx+b with m as the slope, so m = 8.
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Part B
Answer: 40
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The y intercept is 40. This is where the line crosses the y axis. Referring back to y = mx+b form again, we see that y = 8x+40 matches up with b = 40. This point is at the location (0,40).
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Part C
Answer: 64
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Plug in x = 3 and we get
y = 8x+40
y = 8*3+40
y = 24+40
y = 64
We predict a score of 64 when you study for 3 hours
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Part D
In the context of this situation, the y intercept 40 means that if you put in 0 hours of study time, then you expect or predict to get a score of 40 on the test. This is the starting point so to speak because you can't put in negative hours to study.