Noor has 3 T-shirts, 4 blouses and 5 jumpers. She chooses 3 items at random. The random variable X is the number of T-shirts chosen.
Two fair six-sided dice with faces numbered 1, 2, 3, 4, 5, 6 are thrown and the two scores are noted. The difference between the two scores is defined as follows.
Find the expectation of the difference between the two scores.
Two ordinary fair dice are thrown. The resulting score is found as follows.
(i) Draw up the probability distribution table for the score.
(ii) Calculate the expected score.
Three fair 4-sided spinners each have sides labelled 1, 2, 3, 4. The spinners are spun at the same time and the number on the side on which each spinner lands is recorded. The random variable X denotes the highest number recorded.
(a) Show that \(P(X = 2) = \frac{7}{64}\).
(b) Complete the probability distribution table for \(X\).
| x | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| \(P(X = x)\) | \(\frac{7}{64}\) | \(\frac{19}{64}\) |
A particular type of bird lays 1, 2, 3 or 4 eggs in a nest each year. The probability of x eggs is equal to kx, where k is a constant.