A light bulb manufacturer claims its light bulbs will last 500 ...

[haleyc112]

A light bulb manufacturer claims its light bulbs will last 500 hours on average. The lifetime of a light bulb is assumed to follow an exponential distribution.
 a. What is the probability that the light bulb will have to be replaced within 500 hours?
  b. What is the probability that the light bulb will last more than 1,000 hours?
  c. What is the probability that the light bulb will last between 200 and 800 hours?

Question 2

A university planner wants to determine the proportion of spring semester students who will attend summer school. She surveys 32 current students and discovers that 12 will return for summer school.
 a. Construct a 90 confidence interval estimate for the proportion of current spring students who will return for summer school.
 b. With a .95 probability, what sample size would have to be selected to provide a margin of error of 3 or less?

[mariahkathleeen]

Answer to Question 1

a. .632
b. .135
c. .468

Answer to Question 2

a. .234 to .516
b. 1001

[haleyc112]

Correct answers!

[mariahkathleeen]

Great! Please up vote