Edexcel Paper 3 2022 June — Question 6 9 marks

Exam BoardEdexcel
ModulePaper 3 (Paper 3)
Year2022
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicHypothesis test of Pearson’s product-moment correlation coefficient
TypeOne-tailed test for positive correlation
DifficultyStandard +0.3 This is a standard hypothesis test for correlation with routine steps (state hypotheses, compare r=-0.897 to critical value from tables for n=19 at 5% level, conclude). Part (c) requires reversing log transformations using index laws, which is a common Further Maths Statistics technique but straightforward algebraic manipulation. All parts follow textbook procedures with no novel problem-solving required.
Spec1.06d Natural logarithm: ln(x) function and properties2.02c Scatter diagrams and regression lines2.02d Informal interpretation of correlation2.05f Pearson correlation coefficient2.05g Hypothesis test using Pearson's r5.09b Least squares regression: concepts5.09d Linear coding: effect on regression

6. Anna is investigating the relationship between exercise and resting heart rate. She takes a random sample of 19 people in her year at school and records for each person
  • their resting heart rate, \(h\) beats per minute
  • the number of minutes, \(m\), spent exercising each week
Her results are shown on the scatter diagram. \includegraphics[max width=\textwidth, alt={}, center]{3a09f809-fa28-4b3d-bb69-ea074433bd8f-16_531_551_653_740}
  1. Interpret the nature of the relationship between \(h\) and \(m\) Anna codes the data using the formulae $$\begin{aligned} & x = \log _ { 10 } m \\ & y = \log _ { 10 } h \end{aligned}$$ The product moment correlation coefficient between \(x\) and \(y\) is - 0.897
  2. Test whether or not there is significant evidence of a negative correlation between \(x\) and \(y\) You should
    The equation of the line of best fit of \(y\) on \(x\) is $$y = - 0.05 x + 1.92$$
  3. Use the equation of the line of best fit of \(y\) on \(x\) to find a model for \(h\) on \(m\) in the form $$h = a m ^ { k }$$ where \(a\) and \(k\) are constants to be found.

Question 6:
Part (a):
AnswerMarks Guidance
AnswerMark Guidance
eg As the number of minutes exercise (\(m\)) increases the resting heart rate (\(h\)) decreases or the gradient of the curve is becoming flatter with increasing \(m\): diminishing effect of each additional minute of exerciseB1 eg Idea as one increases the other decreases (in context). Allow use of \(m\) and \(h\). eg As \(m\) increases \(h\) decreases. Do not allow negative correlation with no context or \(\rho<0\). Allow there is a negative correlation/association/relationship/exponential between minutes exercise(\(m\)) and resting heart rate (\(h\)) oe
Part (b):
AnswerMarks Guidance
AnswerMark Guidance
\(H_0: \rho=0 \quad H_1: \rho<0\)B1 Both hypotheses correct in terms of \(\rho\) (allow p)
Critical value \(-0.3887\) (Allow \(\pm\))M1 For the cv of \(-0.3887\) or any cv such that \(0.3<
There is evidence that the product moment correlation is less than 0 / there is a negative correlationA1 Independent of hypotheses. Correct conclusion that implies reject \(H_0\) on basis of seeing \(-0.3887\) or if they give 0.3887 we must see comparison \(0.3887<0.897\) and which mentions "pmcc/correlation/relationship" and less than 0/negative or \(\rho<0\). A contradictory statement scores A0 eg Accept \(H_0\) therefore negative correlation
Part (c):
AnswerMarks Guidance
AnswerMark Guidance
\(\log_{10}h = -0.05\log_{10}m + 1.92\)M1 \(h=am^k \rightarrow \log_{10}h = \log_{10}am^k\). Correct substitution for both \(x\) and \(y\). Method 2: Taking the log of both sides
\(\log_{10}h = -\log_{10}m^{0.05}+1.92\) or \(\log_{10}h = \log_{10}m^{-0.05}+1.92\) or \(h=10^{1.92-0.05\log_{10}m}\) oeM1 \(\log_{10}h = \log_{10}a + \log_{10}m^k\) or \(\log_{10}a = 1.92\). Correct use of the power log rule or making \(h\) the subject. Method 2: Correct use of the addition/subtraction log rule
\(\log_{10}hm^{0.05}=1.92\) or \(\log_{10}\left(\frac{h}{m^{-0.05}}\right)=1.92\) or \(h=10^{1.92}\times10^{-0.05\log_{10}m}\) oeM1 \(\log_{10}h = \log_{10}a + k\log_{10}m\). Method 1: Correct use of addition/subtraction log rule or equation in form \(h=10^{1.92}\times10^{-0.05\log m}\). Method 2: A second correct step for correct use of power log rule
\(hm^{0.05}=10^{1.92}\) or \(\frac{h}{m^{-0.05}}=10^{1.92}\) or \(h=10^{1.92}\times10^{\log_{10}m^{-0.05}}\)M1 \(\log_{10}a=1.92\) and \(k=-0.05\). Method 1: Correct removal of logs or \(h=10^{1.92}\times10^{\log m^{-0.05}}\). Method 2: \(\log a\) (or \(a\)) and \(k\) correct
\(h=10^{1.92}m^{-0.05}\) or \(h=83.17...m^{-0.05}\) or \(a=\) awrt 83.17 and \(k=-0.05\)A1 Allow \(h=\) awrt \(83.2m^{-0.05}\). NB award 5/5 for \(a=\) awrt 83.2 and \(k=-0.05\) or \(h=\) awrt \(83.2...m^{-0.05}\) or \(h=10^{1.92}m^{-0.05}\)
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Could you please share the correct pages that contain the actual mark scheme questions and answers? I'd be happy to format them as requested once I can see the relevant content.
# Question 6:

## Part (a):
| Answer | Mark | Guidance |
|--------|------|----------|
| eg As the number of minutes exercise ($m$) increases the resting heart rate ($h$) decreases **or** the gradient of the curve is becoming flatter with increasing $m$: diminishing effect of each additional minute of exercise | B1 | eg Idea as one increases the other decreases (in context). Allow use of $m$ and $h$. eg As $m$ increases $h$ decreases. Do not allow negative correlation with no context or $\rho<0$. Allow there is a negative correlation/association/relationship/exponential between minutes exercise($m$) and resting heart rate ($h$) oe |

## Part (b):
| Answer | Mark | Guidance |
|--------|------|----------|
| $H_0: \rho=0 \quad H_1: \rho<0$ | B1 | Both hypotheses correct in terms of $\rho$ (allow p) |
| Critical value $-0.3887$ (Allow $\pm$) | M1 | For the cv of $-0.3887$ or any cv such that $0.3<|cv|<0.5$ |
| There is evidence that the product moment **correlation** is **less than 0** / **there is a negative correlation** | A1 | Independent of hypotheses. Correct conclusion that implies reject $H_0$ on basis of seeing $-0.3887$ or if they give 0.3887 we must see comparison $0.3887<0.897$ **and** which mentions "pmcc/correlation/relationship" and less than 0/negative or $\rho<0$. A contradictory statement scores A0 eg Accept $H_0$ therefore negative correlation |

## Part (c):
| Answer | Mark | Guidance |
|--------|------|----------|
| $\log_{10}h = -0.05\log_{10}m + 1.92$ | M1 | $h=am^k \rightarrow \log_{10}h = \log_{10}am^k$. Correct substitution for both $x$ and $y$. Method 2: Taking the log of both sides |
| $\log_{10}h = -\log_{10}m^{0.05}+1.92$ or $\log_{10}h = \log_{10}m^{-0.05}+1.92$ or $h=10^{1.92-0.05\log_{10}m}$ oe | M1 | $\log_{10}h = \log_{10}a + \log_{10}m^k$ or $\log_{10}a = 1.92$. Correct use of the power log rule **or** making $h$ the subject. Method 2: Correct use of the addition/subtraction log rule |
| $\log_{10}hm^{0.05}=1.92$ or $\log_{10}\left(\frac{h}{m^{-0.05}}\right)=1.92$ or $h=10^{1.92}\times10^{-0.05\log_{10}m}$ oe | M1 | $\log_{10}h = \log_{10}a + k\log_{10}m$. Method 1: Correct use of addition/subtraction log rule or equation in form $h=10^{1.92}\times10^{-0.05\log m}$. Method 2: A second correct step for correct use of power log rule |
| $hm^{0.05}=10^{1.92}$ or $\frac{h}{m^{-0.05}}=10^{1.92}$ or $h=10^{1.92}\times10^{\log_{10}m^{-0.05}}$ | M1 | $\log_{10}a=1.92$ and $k=-0.05$. Method 1: Correct removal of logs or $h=10^{1.92}\times10^{\log m^{-0.05}}$. Method 2: $\log a$ (or $a$) and $k$ correct |
| $h=10^{1.92}m^{-0.05}$ or $h=83.17...m^{-0.05}$ or $a=$ awrt 83.17 **and** $k=-0.05$ | A1 | Allow $h=$ awrt $83.2m^{-0.05}$. NB award 5/5 for $a=$ awrt 83.2 and $k=-0.05$ or $h=$ awrt $83.2...m^{-0.05}$ or $h=10^{1.92}m^{-0.05}$ |

The images you've shared appear to be essentially blank pages — one completely blank and one showing only a Pearson Education Limited copyright/registration notice at the top.

There is **no mark scheme content** visible on these pages to extract.

Could you please share the correct pages that contain the actual mark scheme questions and answers? I'd be happy to format them as requested once I can see the relevant content.
6. Anna is investigating the relationship between exercise and resting heart rate. She takes a random sample of 19 people in her year at school and records for each person

\begin{itemize}
  \item their resting heart rate, $h$ beats per minute
  \item the number of minutes, $m$, spent exercising each week
\end{itemize}

Her results are shown on the scatter diagram.\\
\includegraphics[max width=\textwidth, alt={}, center]{3a09f809-fa28-4b3d-bb69-ea074433bd8f-16_531_551_653_740}
\begin{enumerate}[label=(\alph*)]
\item Interpret the nature of the relationship between $h$ and $m$

Anna codes the data using the formulae

$$\begin{aligned}
& x = \log _ { 10 } m \\
& y = \log _ { 10 } h
\end{aligned}$$

The product moment correlation coefficient between $x$ and $y$ is - 0.897
\item Test whether or not there is significant evidence of a negative correlation between $x$ and $y$\\
You should

\begin{itemize}
  \item state your hypotheses clearly
  \item use a $5 \%$ level of significance
  \item state the critical value used
\end{itemize}

The equation of the line of best fit of $y$ on $x$ is

$$y = - 0.05 x + 1.92$$
\item Use the equation of the line of best fit of $y$ on $x$ to find a model for $h$ on $m$ in the form

$$h = a m ^ { k }$$

where $a$ and $k$ are constants to be found.
\end{enumerate}

\hfill \mbox{\textit{Edexcel Paper 3 2022 Q6 [9]}}