9709 P51 - Nov 2022 - Q2 - 8 marks
2986
The residents of Persham were surveyed about the reliability of their internet service. 12% rated the service as ‘poor’, 36% rated it as ‘satisfactory’ and 52% rated it as ‘good’.
A random sample of 8 residents of Persham is chosen.
(a) Find the probability that more than 2 and fewer than 8 of them rate their internet service as poor or satisfactory. [3]
A random sample of 125 residents of Persham is now chosen.
(b) Use an approximation to find the probability that more than 72 of these residents rate their internet service as good. [5]
