Suppose the least squares regression line for a set of data has slope 72.4. Now

Question

Suppose the least squares regression line for a set of data has slope 72.4. Now suppose remove a point from the data, compute the least-squares regression line, and find that the new slope is 8.7. The point removed would be considered influential a residual a response A researcher obtained the average SAT scores of all students in each of the 50 states, and the average teacher salaries in each of the 50 states. She found a negative correlation between these variables. The researcher concluded that a lurking variable must be present. By lurking variable she means a variable that is not among the variables studied, but that affects the response variable the true cause of a response any variable that produces a large residual the true variable, which is explained by the explanatory variable Curiously, during months when sales of beer are above average, sales of ice cream also tend to be above average, during months when sales of beer are below average, sales of ice cream also tend to be below average. Which of the following can we conclude from these facts? The correlation between "beer sales" and ice cream sales is negative For a lot of people drinking beer causes a desire for ice cream, or vice versa A scatter plot of monthly ice cream sales versus monthly beer sales would show that a straight line describes the pattern in the plot, but it would have to be a horizontal line. None of the choices are correct.

Explanation / Answer

Question 23:

Correct option:

Influential point.

REASON:

By definition, an influential point is an outlier that greatly affects the slope of the regression line. One way to test the influence of an outlier is to compute the regresion equation with and without the outlier.

Question 24:

Correct option:

a variable that is not among the variables studied but that affects the response variable.

REASON:

By definition, a lurking variable is a variable that is not included as an explanatory or response variable in the analysis but can affect the interpretation of relationship between variables.

Question 25:

Correct option:

For a lot of people , drinking beer causes a desire for ice cream , or vice versa.

REASON:

As per the given statement, there is a direct relatiion existing between beer and ice cream : i.e., more beer is connected to more ice ream and less beer is connected to less ice cream.

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