7 In regression analysis a decreasing r2 value means a The r

7) In regression analysis a decreasing r2 value means:
a. The regression coefficient is declining
b. The slope is declining
c. the proportion of variation in X explained by Y is decreasing
d. the proportion of variation in Y explained by X is decreasing
8) In which of the following situations would it be most appropriate to use correlation instead of regression? (assume all the variables are normally distributed, and think about whether there is a causal relationship)
a. arm length and body mass
b. annual salary and years of education
c. grade in a class and hours of studying
d. the number of chickadee “dee” calls and the size of their predators.

Solution

7.

As r^2 is the proportion of variation in Y explained by X, then it is

OPTION D: the proportion of variation in Y explained by X is decreasing. [answer, D]

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8.

It is more appropriate to use correlaion instead of regression if you just want to establish relationship, but wouldn\'t want to be so precise.

In that case, it would be

OPTION A: arm length and body mass [ANSWER]