Question

Helmets and lunches.

The scatterplot shows the relationship between socioeconomic status measured as the percentage of children in a neighborhood receiving reduced-fee lunches at school and the percentage of bike riders in the neighborhood wearing helmets.

% Recieving reduced lunch           % Wearing helmets

6                                              39

3                                              64

15                                           34

21                                           24

20                                           57

18                                           33

38                                           50

33                                           40

52                                           32

43                                           33

80                                           12

75                                           12

(a) Compute the correlation coefficient between rates of receiving reduced lunch (as a percentage) and rates of helmet wear (as a percentage). r= .

(b) The correlation between receiving reduced lunch and wearing helmets is .

(c) Compute r2: .

(d) What proportion of the response variable may be explained by the explanatory variable ? .

(e) Compute the regression line. y= x+ .

(f) According to our model, if a neighborhood had 35% children receiving reduced lunch, the percentage wearing helmets would be %.

(g) According to our model, if the percentage of children in a neighborhood wearing helmets is 35%, the percentage who receive reduced lunch would be %

.

Answer 1