Answer:
slope = 1
Step-by-step explanation:
Calculate the slope m using the slope formula
m = 
with (x₁, y₁ ) = (- 1, 0) and (x₂, y₂ ) = (0, 1) ← 2 points on the line
m =
= 1
Cohen's d is calculated according to the formula:
d = (mean difference) / standard deviation
0.5 = mean difference / 12
Therefore, mean difference = 6
Since we have a population mean of 80, the sample mean must be 80 + 6 = 86.
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