Question

Listed below are the number of calories and the number of milligrams of cholesterol of fast-
food chicken sandwiches from seven restaurants.

Calories, x	390	535	720	300	430	500	440
Cholesterol, y	43	45	80	50	55	52	60

a) Find the value of the linear correlation coefficient r and use a significance level of α = 0.05 to
determine whether there is a significant linear correlation between the two variables.

b) Find the best prediction for the cholesterol in a 600 calorie chicken sandwich.

Answer 1

a)

correlation coefficient r=

Sxy/(√Sxx*Syy) =

0.725

for n=7 and 0.05 level; critical value =0.754

since  correlation coefficient r is not higher than critical value , we can not conclude that  there is a significant linear correlation between the two variables.

b)

best prediction for the cholesterol in a 600 calorie chicken sandwich =average of y values =55.00