(a(i))[2]
Complete the scatter diagram on the grid. The first six points are already plotted.
(a(ii))[1]
Runners with a 400 metres time of less than $55$ seconds and an 800 metres time of less than $125$ seconds are chosen for an athletics competition. How many runners are chosen for the competition?
(a(iii))[1]
What correlation is shown by the scatter diagram?
(a(iv))[1]
Draw a line of best fit on the scatter diagram.
(a(v))[1]
A different runner took $65$ seconds for 400 metres. Use your line of best fit to estimate the time they would need for 800 metres.
(b(i))[1]
Explain why $p+q=12$.
(b(ii))[2]
Show that $142.5p + 162.5q = 1870$.
(b(iii))[3]
Find the values of $p$ and $q$. Show your working.