2. A company produces chocolate chip biscuits. The number of chocolate chips per biscuit has a Poisson distribution with mean 8
- Find the probability that one of these biscuits, selected at random, does not contain 8 chocolate chips.
A small packet contains 4 of these biscuits, selected at random.
- Find the probability that each biscuit in the packet contains at least 8 chocolate chips.
A large packet contains 9 of these biscuits, selected at random.
- Use a suitable approximation to find the probability that there are more than 75 chocolate chips in the packet.
A shop sells packets of biscuits, randomly, at a rate of 1.5 packets per hour. Following an advertising campaign, 11 packets are sold in 4 hours.
- Test, at the \(5 \%\) level of significance, whether or not there is evidence that the rate of sales of packets of biscuits has increased. State your hypotheses clearly.