Twenty values of x are summarised by (x 1) 2 = 132 and (x 1) =
Question:
Twenty values of x are summarised by Σ(x −1)2 = 132 and Σ(x −1) = 44.
Eighty values of y are summarised by Σ(y +1)2 = 17 704 and Σ(y +1) = 1184.
a. Show that Σx = 64 and that Σx2 = 240.
b. Calculate the value of Σy and of Σ
Each year Upchester United plays against Upchester City in a local derby match. The number of goals scored in a match by United is denoted by u and the number of goals scored in a match by City is denoted by c. The number of goals scored in the past 15 matches are summarised by Σ(u −1)2 = 25, Σ(u −1) = 9, Σc2 = 39 and Σc = 19.
a. How many goals have been scored altogether in these 15 matches?
b. Show that Σu2 = 58.
c. Find, correct to 3 decimal places, the variance of the number of goals scored by the two teams together in these 15 matches.
y2.
d. Find the exact variance of the 100 values of x and y combined.
Step by Step Answer:
Cambridge International AS & A Level Mathematics Probability & Statistics 1 Coursebook
ISBN: 9781108407304
1st Edition
Authors: Dean Chalmers, Julian Gilbey