Questions: Before calculating the regression line, you expect the slope to be negative based on the points you plotted, suggesting that there may be a negative linear relationship between fatigue and depression.
For the data above, the value of X̄=5, Y=6.35, covXY=-7.500, sX²=10.000, and sY²=9.644. Find the regression line for predicting Y given X. The slope of the regression line is approximately -0.75, and the Y intercept is approximately 10.1.
The Pearson correlation is r=-0.7637 approximately. The variation amount in the depression scores (explained by their fatigue scores) is
The standard error of the estimate is
Suppose you want to predict the depression score for a new patient. The only information given is that this new patient is similar to patients A through E; therefore, your best guess for the new patient's level of depression is The error associated with this guess (that is, the "standard" amount your guess will be away from the true value) is
Transcript text: Before calculating the regression line, you expect the slope to be negative based on the points you plotted, suggesting that there may be a negative $\nabla$ linear relationship between fatigue and depression.
For the data above, the value of $\bar{X}=5, Y=6.35, \operatorname{cov}_{X Y}=-7.500, s_{X}^{2}=10.000$, and $s_{Y}^{2}=9.644$.
Find the regression line for predicting $Y$ given $X$. The slope of the regression line is $\underline{-0.75} \boldsymbol{\sim}$, and the $Y$ intercept is $10.1 \sim$.
The Pearson correlation is $\mathrm{r}=-0.7637 \sim$. The variation amount in the depression scores (explained by their fatigue scores) is
The standard error of the estimate is
Suppose you want to predict the depression score for a new patient. The only information given is that this new patient is similar to patients A through E; therefore, your best guess for the new patient's level of depression is The error associated with this guess (that is, the "standard" amount your guess will be away from the true value) is
Solution
Solution Steps
Step 1: Determine the slope
The slope of the regression line (b) is given by the formula: b = covxy / sx2.
Substituting the given values: b = -7.5 / 10 = -0.75
Step 2: Determine the y-intercept
The y-intercept (a) can be calculated with the formula: a = Y̅ - b * X̅.
Substituting given values: a = 6.35 - (-0.75) * 5 = 6.35 + 3.75 = 10.1
Step 3: Determine the Pearson correlation (r)
Pearson correlation (r) is the square root of the coefficient of determination (r2) and can be calculated by r = covxy / (Sx * Sy). First calculate Sy by taking the square root of sy2, which is sqrt(9.644), which is roughly 3.105. Now, we plug in our values to get r = -7.5 / (sqrt(10) * 3.105) ≈ -7.5 / (3.162 * 3.105) ≈ -0.7637.
Final Answer:
The slope of the regression line is -0.75, the y-intercept is 10.1, and the Pearson correlation is approximately -0.76.