Part 1: A fleet of rental cars - all the same make, model, and year - has a mean
ID: 3156381 • Letter: P
Question
Part 1: A fleet of rental cars - all the same make, model, and year - has a mean fuel efficiency of 23.4 miles per gallon (mpg). A random sample of 56 cars are selected and the air filter of each is replaced with a new one. Let be the population mean fuel efficiency score that would occur if every car's air filter were replaced. The air filter change is deemed effective if u> 23.4mpg. A test is made of Ho:u=23.4 versus H1:u>23.44. Assume that the air filter changes are not effective. Which type of error is impossible?
A) Type I B) Type II
Part 2: A fleet of rental cars - all the same make, model, and year - has a mean fuel efficiency of 24.3 miles per gallon (mpg). A random sample of 41 cars are selected and the air filter of each is replaced with a new one. Let be the population mean fuel efficiency score that would occur if every car's air filter were replaced. The air filter change is deemed effective if u> 24.3 mpg. A test is made of Ho:u=24.3 versus H1:u>24.3. Assume the air filter changes are effective but the conclusion is reached that the changes might not be effective. Which type of error, of any, has occured?
A) Type II B Mechanical Failure C) Type I D) No Error - correct decision
Explanation / Answer
A)Type II error is impossible.A type II error is failing to detect an effect that is present.
B)Type I error has occured. In statistical hypothesis testing, a type I error is the incorrect rejection of a true null hypothesis (a "false positive").