# Question

If the number of minutes that a doctor spends with a patient is a random variable having an exponential distribution with the parameter θ = 9, what are the probabilities that it will take the doctor at least 20 minutes to treat

(a) One patient;

(b) Two patients;

(c) Three patients?

(a) One patient;

(b) Two patients;

(c) Three patients?

## Answer to relevant Questions

If X is the number of 7’s obtained when rolling a pair of dice three times, find the probability that Y = X2 will exceed 2. If the joint density of X and Y is given by And Z = X + Y / 2 , find the probability density of Z by the distribution function technique. Find the mean and the variance of the finite population that consists of the 10 numbers 15, 13, 18, 10, 6, 21, 7, 11, 20, and 9. Use Theorem 8.11 to show that, for random samples of size n from a normal population with the variance σ2, the sampling distribution of S2 has the mean σ2 and the variance 2σ4/n–1. (A general formula for the variance of ...Use the transformation technique based on Theorem 7.2 on page 218 to rework the proof of Theorem 8.14. Let f = u/v1 v/v2 and w = v.)Post your question

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