Given that 5.3% of newborn babies have a low birth weight, find $w$.

A newborn baby has a low birth weight.

Find the probability that the baby weighs at least 2.15 kg.

valid approach     (M1)

eg$\,\,\,\,\,$$z =  - 1.61643$, 

2.48863

$w = 2.49{\text{ (kg)}}$     A2     N3

[3 marks]

correct value or expression (seen anywhere)

eg$\,\,\,\,\,$$0.053 - {\text{P}}(X \leqslant 2.15),{\text{ }}0.039465$     (A1)

evidence of conditional probability     (M1)

eg$\,\,\,\,\,$$\frac{{{\text{P}}(2.15 \leqslant X \leqslant w}}{{{\text{P}}(X \leqslant w)}},{\text{ }}\frac{{0.039465}}{{0.053}}$

0.744631

0.745     A1     N2

[3 marks]