Answer it
P1 a4 regression line
4 marksYou mark it yourself against the marking points
A school café records how many cups of hot chocolate it sells each day and the outdoor temperature at noon. All of its records are from days between 0 °C and 25 °C. It fits a linear regression line to the records:
cups sold = 180 - 6 × temperature
(a) Calculate the number of cups the line predicts on a day when the temperature is 15 °C. [1]
(b) State what the number 6 in the equation tells the café. [1]
(c) Calculate the prediction for a day at -10 °C, and explain why it should not be trusted. [2]
[4]