GCSE Secondary Maths Age 13-17 - Probability & Statistics: Scatter Diagram - Explained

The video tutorial discusses a survey that recorded outside temperatures and electricity usage for heating in 10 homes. It evaluates Molly's claim that electricity usage decreases by 4 units per degree Celsius increase in temperature. The instructor demonstrates how to draw a line of best fit and calculate its gradient, concluding that the decrease is 2.4 units, not 4. The tutorial also explains why the line of best fit should not be used to predict electricity usage at 30 degrees Celsius, as it falls outside the data range.

What does the horizontal axis represent in the scatter diagram discussed in the video?

• Number of homes surveyed

• Number of units of electricity used

• Outside temperature in degrees Celsius

• Time of the day

What is Molly's hypothesis regarding electricity usage and temperature?

• Electricity usage increases by 4 units per degree Celsius increase

• Electricity usage remains constant regardless of temperature

• Electricity usage decreases by 2 units per degree Celsius increase

• Electricity usage decreases by 4 units per degree Celsius increase

What is the calculated rate of decrease in electricity usage per degree Celsius increase, according to the line of best fit?

• 2.4 units

• 1.5 units

• 4 units

• 3 units

Why is it not advisable to use the line of best fit to predict electricity usage at 30 degrees Celsius?

• The line of best fit is inaccurate

• The line of best fit is not drawn correctly

• The data only goes up to 20 degrees Celsius

• The temperature does not affect electricity usage

What is the importance of staying within the data range when using a line of best fit?

• To make the graph look better

• To increase the number of data points

• To ensure predictions are accurate

• To avoid using complex calculations