Date | November 2021 | Marks available | 1 | Reference code | 21N.1.SL.TZ0.1 |
Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 0 |
Command term | Comment | Question number | 1 | Adapted from | N/A |
Question
Eduardo believes that there is a linear relationship between the age of a male runner and the time it takes them to run metres.
To test this, he recorded the age, years, and the time, minutes, for eight males in a single race. His results are presented in the following table and scatter diagram.
Eduardo looked in a sports science text book. He found that the following information about was appropriate for athletic performance.
For this data, find the value of the Pearson’s product-moment correlation coefficient, .
Comment on your answer to part (a), using the information that Eduardo found.
Write down the equation of the regression line of on , in the form .
A 57-year-old male also ran in the race.
Use the equation of the regression line to estimate the time he took to complete the race.
Markscheme
A2
[2 marks]
strong A1
Note: Answer may include “positive”, however this is not necessary for the mark.
[1 mark]
A1
Note: Condone in place of . Answer must be an equation.
[1 mark]
(M1)
Note: Award (M1) for correct substitution into their regression line.
A1
Note: Accept and from use of sf and/or sf values.
[2 marks]
Examiners report
Generally, a good starting point for most candidates. Most of them could find the correlation coefficient with a correct interpretation. They could find the regression equation and use it appropriately to make a prediction. It was observed that candidates used a mixture of two and three significant figures to reach an answer. Marks were generally awarded for their correct three significant answers or answers given to a higher degree of accuracy. The weaker candidates substituted instead of years into their equation.
Generally, a good starting point for most candidates. Most of them could find the correlation coefficient with a correct interpretation. They could find the regression equation and use it appropriately to make a prediction. It was observed that candidates used a mixture of two and three significant figures to reach an answer. Marks were generally awarded for their correct three significant answers or answers given to a higher degree of accuracy. The weaker candidates substituted instead of years into their equation.
Generally, a good starting point for most candidates. Most of them could find the correlation coefficient with a correct interpretation. They could find the regression equation and use it appropriately to make a prediction. It was observed that candidates used a mixture of two and three significant figures to reach an answer. Marks were generally awarded for their correct three significant answers or answers given to a higher degree of accuracy. The weaker candidates substituted instead of years into their equation.
Generally, a good starting point for most candidates. Most of them could find the correlation coefficient with a correct interpretation. They could find the regression equation and use it appropriately to make a prediction. It was observed that candidates used a mixture of two and three significant figures to reach an answer. Marks were generally awarded for their correct three significant answers or answers given to a higher degree of accuracy. The weaker candidates substituted instead of years into their equation.