Question

1. If we perform a regression, using data from 157 countries, with life expectancy as the y-variable and infant mortality rate as the x-variable, we get R² = 0.81. Which of the following is true

a.Differences in infant mortality rates among countries can explain 81 percent of the variability in life expectancy.

b.Because R2 is so high, we can be sure that linear regression is appropriate.

c.We can accurately predict life expectancy from infant mortality in 81 percent of countries.

d.We can conclude that high infant mortality is the primary cause of low life expectancy.

2. In which instance below is linear regression never appropriate

a. If the residual plot shows curvature.

b. If the data set contains an outlier.

c. If the R2 value is below 0.20.

d. No answer text provided.

Answer 1