# 8.04 Interpreting and making predictions

## Interactive practice questions

Consider the following set of data.

The equation of the least squares line fitted to this data is approximately $y=3.15-0.18x$y=3.150.18x.

 $x$x $y$y $0.8$0.8 $1.77$1.77 $2.7$2.7 $3.62$3.62 $4.9$4.9 $5.7$5.7 $7$7 $8.6$8.6 $10.1$10.1 $3.4$3.4 $2.9$2.9 $2.5$2.5 $2.4$2.4 $1.9$1.9 $1.9$1.9 $1.8$1.8 $1.7$1.7 $1.54$1.54
a

Predict the value of $y$y when $x=3$x=3 using the least square line.

b

Is this an interpolation or extrapolation?

Interpolation

A

Extrapolation

B

Interpolation

A

Extrapolation

B
Easy
Approx a minute

Consider the following set of data.

The equation of the least squares line fitted to this data is approximately $y=3.15-0.18x$y=3.150.18x.

Consider the following set of data.

The equation of the least squares line fitted to this data is approximately given by $\text{Average test score}=70.34-1.92\times\text{Number of tests}$Average test score=70.341.92×Number of tests.

A least squares regression line is given by $y=3.59x+6.72$y=3.59x+6.72.

### Outcomes

#### 9.D1.3

Create a scatter plot to represent the relationship between two variables, determine the correlation between these variables by testing different regression models using technology, and use a model to make predictions when appropriate.

#### 9.D2.1

Describe the value of mathematical modelling and how it is used in real life to inform decisions.