6 The demand for a WWSatNav at a superstore may be modelled by a Poisson distribution with a mean of 2.5 per day. The superstore is open 6 days each week, from Monday morning to Saturday evening.
- Determine the probability that the demand for WWSatNavs during a particular week is at most 18 .
- The superstore receives a delivery of WWSatNavs on each Sunday evening. The manager, Meena, requires that the probability of WWSatNavs being out of stock during a week should be at most \(5 \%\).
Determine the minimum number of WWSatNavs that Meena requires to be in stock after a delivery.
- Use a distributional approximation to estimate the probability that the demand for WWSatNavs during a period of \(\mathbf { 2 }\) weeks is more than 35.
- Changes to the superstore's delivery schedule result in it receiving a delivery of WWSatNavs on alternate Sunday evenings. Meena now requires that the probability of WWSatNavs being out of stock during the 2 weeks following a delivery should be at most \(5 \%\).
Use a distributional approximation to determine the minimum number of WWSatNavs that Meena now requires to be in stock after a delivery.
(3 marks)