The normal distributionEdexcel A-Level Maths: Mind map

Exam questions on The normal distribution

1. The height, $H$ cm, of a plant of a certain variety is modelled by $H\sim N(42,3^2)$.
   Find the probability that a plant chosen at random has a height between 38 cm and 47 cm.2 marks
2. Scores on a reasoning test are modelled by $X\sim N(100,15^2)$.
   Find the score that is exceeded by 10% of people.2 marks
3. The lifetime, $L$ hours, of a type of battery is modelled by $L\sim N(\mu,\sigma^2)$. It is found that $P(L<200)=0.1$ and $P(L>260)=0.2$.
   Show that $\mu-1.2816\sigma=200$ and $\mu+0.8416\sigma=260$.3 marks