Question

2. (4 pts) 60% of attendees at a sales conference are men. If you pick a random sample of 18 attendees,

a. Find the probability of exactly 10 men being selected.

b. If you were asked to find the probability of exactly 8 women being selected, would your answer be the same as in part a?

c. Find the probability of less than 12 men being selected.

d. Find the probability of no women in the sample.

3. (4 pts) Using a normal distribution having mean of 200 and standard deviation of 15.0, calculate the following probabilities:

a. P(X <= 180)

b. P(X<=220)

c. P(X >= 220)

d. P(180 <= X <= 220)

4. (3pts) The lifetimes of certain types of car battery are normally distributed with a mean of 1258 days and a standard deviation of 185 days. If the supplier guarantees them for 1000 days, what proportion of batteries are expected to fail sooner than 1000 days, subject to replacement under the guarantee?

Answer 1