Everything Maths Grade 12

CHAPTER 11. STATISTICS 11.4

SOLUTION

appliance x y xy x^2

1 5 90 450 25

2 10 140 1400 100

3 15 250 3750 225

4 20 300 6000 400

5 30 380 11400 900

Total 80 1160 23000 1650

b =

n

�

xy−

�

x

�

y

n

�

x^2 − (

�

x)^2

=

5 × 23000 − 80 × 1160

5 × 1650 − 802

= 12

a = ̄−y b ̄x =

1160

5

−

12 × 80

5

= 40

∴ ˆ = 40 + 12y x

Using a Calculator EMCCZ

Example 3: Using the Sharp EL-531VH calculator

QUESTION

Find a regression equation for the following data:

Days (x) 1 2 3 4 5

Growth in m (y) 1 , 00 2 , 50 2 , 75 3 , 00 3 , 50

SOLUTION

Step 1 : Getting your calculator ready

Using your calculator, change the mode from normal to “Stat xy”. This mode

enables you to type in bivariate data.

Step 2 : Entering the data

Key in the data as follows: