| Exam Board | OCR |
|---|---|
| Module | S1 (Statistics 1) |
| Year | 2008 |
| Session | January |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Conditional Probability |
| Type | Given conditional, find joint or marginal |
| Difficulty | Easy -1.2 This is a straightforward conditional probability question requiring only direct application of P(A|B) = P(A∩B)/P(B) with all necessary probabilities given explicitly. Part (i) is a one-step calculation, and part (ii) requires simple subtraction. No problem-solving insight needed, just routine formula application. |
| Spec | 2.03d Calculate conditional probability: from first principles |
4 A supermarket has a large stock of eggs. 40\% of the stock are from a firm called Eggzact. 12\% of the stock are brown eggs from Eggzact.
An egg is chosen at random from the stock. Calculate the probability that\\
(i) this egg is brown, given that it is from Eggzact,\\
(ii) this egg is from Eggzact and is not brown.
\hfill \mbox{\textit{OCR S1 2008 Q4 [4]}}