Calculate the exact value of the mean length.

Write your answer to part (a) in the form a × 10^k where 1 ≤ a < 10 and $k \in \mathbb{Z}$.

Marian calculates the mean length and finds it to be 105 cm.

Calculate the percentage error made by Marian.

$\left( {\frac{{104.5 + 105.1 + ...}}{6}} \right)$     (M1)

Note: Award (M1) for use of mean formula.

= 104.9 (cm)     (A1)     (C2)

[2 marks]

1.049 × 10²     (A1)(ft)(A1)(ft)     (C2)

Notes: Award (A1)(ft) for 1.049, (A1)(ft) for 10². Follow through from their part (a).

[2 marks]

$\frac{{105 - 104.9}}{{104.9}} \times 100$  (%)     (M1)

Notes: Award (M1) for their correctly substituted % error formula.

% error = 0.0953  (%)     (0.0953288...)     (A1)(ft)     (C2)

Notes: A 2sf answer of 0.095 following $\frac{{105 - 104.9}}{{105}} \times 100$ working is awarded no marks. Follow through from their part (a), provided it is not 105. Do not accept a negative answer. % sign not required.

[2 marks]

Another well answered question with candidates showing a good understanding of standard form and many correct answers were seen in parts (a) and (b). Whilst the formula is given for percentage error, there were still a minority of candidates who divided by 105 rather than the required value of 104.9.

Another well answered question with candidates showing a good understanding of standard form and many correct answers were seen in parts (a) and (b). Whilst the formula is given for percentage error, there were still a minority of candidates who divided by 105 rather than the required value of 104.9.

Another well answered question with candidates showing a good understanding of standard form and many correct answers were seen in parts (a) and (b). Whilst the formula is given for percentage error, there were still a minority of candidates who divided by 105 rather than the required value of 104.9.