Everything Maths Grade 12

11.4 CHAPTER 11. STATISTICS

1 (x,y) 1 DATA n = 1

2 (x,y) 2 , 5 DATA n = 2

3 (x,y) 2 , 75 DATA n = 3

4 (x,y) 3 , 0 DATA n = 4

5 (x,y) 3 , 5 DATA n = 5

Step 3 : Getting regression results from the calculator

Ask for the values of theregression coefficients a and b.

RCL a gives a = 0, 9

RCL b gives b = 0, 55

∴ ˆ = 0y ,9 + 0, 55 x

Example 4: Using the CASIO fx-82ES Natural Display calculator

QUESTION

Using a calculator determine the least squaresline of best fit for the following data set of

marks.

Learner 1 2 3 4 5

Chemistry (%) 52 55 86 71 45

Accounting (%) 48 64 95 79 50

For a Chemistry mark of 65%, what mark does the least squares line predict for Account-

ing?

SOLUTION

Step 1 : Getting your calculator ready

Switch on the calculator. Press [MODE] and then select STAT by pressing [2].

The following screen will appear:

1 1 −VAR 2 A +BX

3 +CX^24 ln X

5 eˆX 6 A.BˆX

7 A.XˆB 8 1 /X

Now press [2] for linearregression. Your screenshould look something like this:

x y

1

2

3

Step 2 : Entering the data