2 The number of computers, \(A\), bought during one day from the Amplebuy computer store can be modelled by a Poisson distribution with a mean of 3.5.
The number of computers, \(B\), bought during one day from the Bestbuy computer store can be modelled by a Poisson distribution with a mean of 5.0 .
- Calculate \(\mathrm { P } ( A = 4 )\).
- Determine \(\mathrm { P } ( B \leqslant 6 )\).
- Find the probability that a total of fewer than 10 computers is bought from these two stores on one particular day.
- Calculate the probability that a total of fewer than 10 computers is bought from these two stores on at least 4 out of 5 consecutive days.
- The numbers of computers bought from the Choicebuy computer store over a 10-day period are recorded as
$$\begin{array} { l l l l l l l l l l }
8 & 12 & 6 & 6 & 9 & 15 & 10 & 8 & 6 & 12
\end{array}$$
- Calculate the mean and variance of these data.
- State, giving a reason based on your results in part (c)(i), whether or not a Poisson distribution provides a suitable model for these data.