When conducting a hypothesis test for the population mean when ...

[mspears3]

When conducting a hypothesis test for the population mean when sigma is known and the sample size is 30 or more, the test statistic follows the ___________________ ____________.
 
  A) Student's t-distribution
  B) binomial distribution
  C) normal distribution
  D) exponential distribution

Question 2

Suppose the average tread-life of a certain brand of tire is 42,000 miles and that this mileage follows the exponential probability distribution.
 
  What is the probability that a randomly selected tire will have a tread-life between 30,000 and 50,000 miles?A) 0.1854
  B) 0.2719
  C) 0.5105
  D) 0.6959

[reversalruiz]

Answer to Question 1

C

Answer to Question 2

A