Lube-Tech is a major chain whose primary business is performing ...

[lilldybug07]

Lube-Tech is a major chain whose primary business is performing lube and oil changes for passenger vehicles.
 
  The national operations manager has stated in an industry newsletter that the mean number of miles between oil changes for all passenger cars exceeds 4,200 miles. To test this, an industry group has selected a random sample of 100 vehicles that have come into a lube shop and determined the number of miles since the last oil change and lube. The sample mean was 4,278 and the standard deviation was known to be 780 miles. Based on a significance level of 0.10, the critical value for the test is approximately z = 1.28. Indicate whether the statement is true or false

Question 2

A normally distributed population has a mean of 500 and a standard deviation of 60. Determine the probability that a random sample of size 25 selected from the population will have a sample mean greater than or equal to 515.
 
  A) 0.1056
  B) 0.1761
  C) 0.0712
  D) 0.0151

[elizabethrperez]

Answer to Question 1

TRUE

Answer to Question 2

A

[lilldybug07]

Gracias!

[smrtceo]

Thanks for the timely response, appreciate it