Fuel consumption (in litres per 100 kilometres) was measured for 13 different speeds of a particular car.
Speed (km/h) - X Fuel consumption (L/100 km) - Y
30 5.7
40 5
50 5.2
60 5.6
70 6.2
80 6.8
90 7.5
100 8.2
110 9
120 10
130 11
140 12.5
150 13.5
Based on this data set, is there a linear correlation between car speed and fuel consumption ?
Back up your argument with the calculation of the coefficient of linear correlation (r), then choose the best statement from the ones provided below:
Group of answer choices
• The linear correlation coefficient is between -1.0 and -0.90, representing a strong, negative linear relationship. This means that an increment in car speed is accompanied by a consistent decrement in fuel used.
• The linear correlation coefficient is somewhere between -0.30 and -0.50, representing a weak, negative linear correlation. This means that as car speed increases, fuel used efficiency decreases, but this decrement is not consistent.
• The linear correlation coefficient is above 0.90, representing a strong, positive linear relationship. This means that an increment in car speed is accompanied by a consistent increment in fuel consumption.
• The linear correlation coefficient is somewhere between -0.30 and 0.30, representing no relationship between the two variables. This means that as car speed increases, there is no clear tendency for fuel used to change.
• The linear correlation coefficient is somewhere between 0.30 and 0.50, representing a weak, positive linear correlation. This means that as car speed increases, fuel used also increases, but the increment is not consistent.