Suppose that you choose a letter at random from the word sta
Suppose that you choose a letter at random from the word “statistics? and that you continue to choose letters at random (without replacement) until you select a vowel. Let the random variable Y represent the number of letters that you choose in order to get a vowel.
(a) Determine the probability distribution of Y .
(b) Repeat part (a) in the case that the sampling is performed with replacement.
Solution
Here total alphabets =10 , among them vowels 3 and the remaining 7 are consonants.
The probability distribution of Y is
b) In the case of replacement, probability of a getting a vowel =3/10
probability of not getting a vowel = 7/10
Let \'Y\' be the number of letters that you choose in order to get vowel is
P(Y=y) =(0.7)^y-1 * (0.3)
| Y | P(y) |
| 1 | 0.3 |
| 2 | 0.233333 |
| 3 | 0.175 |
| 4 | 0.125 |
| 5 | 0.083333 |
| 6 | 0.05 |
| 7 | 0.025 |
| 8 | 0.008333 |
| Total | 1 |
