Course home

2.2.3 Central tendency, variation and standard deviation

Easy Medium Hard

1 2 3 4 5 6 7 8 9 10 11

Question 8

The times, $t\,$ seconds, taken by 30 cars to accelerate from rest to a fixed speed are coded using

$y=t−ab\displaystyle y = \frac{t - a}{b}$

where $a\,$ and $b\,$ are constants and $b > 0$ .

The 30 coded values have mean 4 and standard deviation 2.5. The 30 original times have mean 74 seconds and standard deviation 12.5 seconds.

Find the value of $b$ .

[2]

Find the value of $a$ .

[2]

The median of the coded values is 3.6. Find the median of the original times.

[2]

Markscheme

2.2.3 Central tendency, variation and standard deviation Questions

A Level
Maths
2.2.3 Central tendency, variation and standard deviation

39 exam-style questions on AQA A Level Maths 2.2.3 Central tendency, variation and standard deviation. Each one has a worked solution and a mark scheme showing where the marks go.

2.2.3 Central tendency, variation and standard deviation

Question bank

2.2.3 Central tendency, variation and standard deviation

Easy Medium Hard

1 2 3 4 5 6 7 8 9 10 11

Question 8

The times, $t\,$ seconds, taken by 30 cars to accelerate from rest to a fixed speed are coded using

$y=t−ab\displaystyle y = \frac{t - a}{b}$

where $a\,$ and $b\,$ are constants and $b > 0$ .

The 30 coded values have mean 4 and standard deviation 2.5. The 30 original times have mean 74 seconds and standard deviation 12.5 seconds.

Find the value of $b$ .

[2]

Find the value of $a$ .

[2]

The median of the coded values is 3.6. Find the median of the original times.

[2]

Markscheme

2.2.3 Central tendency, variation and standard deviation Questions

A Level
Maths
2.2.3 Central tendency, variation and standard deviation

39 exam-style questions on AQA A Level Maths 2.2.3 Central tendency, variation and standard deviation. Each one has a worked solution and a mark scheme showing where the marks go.