Might we be able to predict life expectancies from birthrates?
Below are bivariate data giving birthrate and life expectancy information for each of twelve countries. For each of the
countries, both x, the number of births per one thousand people in the population, and y, the
female life expectancy (
im
years), are given. Also shown are the scatter plot for the data and the least-squares
regression line. The equation for t
line is y 80.85-0.44 x.
Birthrate, x
(number of births per 1000
Female life expectancy, y
(in years)
people)
85-
51.0
60.4
45.6
58.7
25.9
73.9
30.7
62.2
49.6
61.6
18.7
71.6
64.1
40.2
71.4
Female life expectancy
(in years)
80+
75-
x
70-
65-
60-
55
50
27.6
12.3
72.2
67.7
35.8
75.6
14.5
10 15 20 25 30 35 40 45 30 3360
Birthrate
(number of births per 1000 people)
53.1
51.2
Send data to calc... v
Based on the sample data and the regression line, answer the following.
(a) From the regression equation, what is the predicted female life expectancy (in years) when
the birthrate is 49.6
births per 1000 people? Round your answer to one or more decimal
places.
58.4
(b) What was the observed female life expectancy (in years) when the birthrate was 49.6 births
per 1000 people?
62.4
X
