Question

A company seeks to employ a new public relations manager. The hiring committee surveys 10 public relations managers and finds the average salary is $104652.343 with standard deviation of $1762.4067. What is the 95% confidence interval for the true average public relations manager salary?

Question 1 options:

1)	( 104650.081 , 104654.605 )

2)	( -103391.593 , 105913.093 )

3)	( 104095.021 , 105209.665 )

4)	( 103410.63 , 105894.056 )

5)	( 103391.593 , 105913.093 )

Suppose you work for Fender Guitar Company and you are responsible for testing the integrity of a new formulation of guitar strings. To perform your analysis, you randomly select 42 'high E' strings and put them into a machine that simulates string plucking thousands of times per minute. You record the number of plucks each string takes before failure and compile a dataset. You find that the average number of plucks is 6,029.2 with a standard deviation of 183.19. A 95% confidence interval for the average number of plucks to failure is (5,972.1, 6,086.3). From the option listed below, what is the appropriate interpretation of this interval?

Question 2 options:

1)	We are 95% confident that the proportion of all 'high E' guitar strings fail with a rate between 5,972.1 and 6,086.3.

2)	We are 95% confident that the average number of plucks to failure for all 'high E' strings is between 5,972.1 and 6,086.3.

3)	We are certain that 95% of the average number of plucks to failure for all 'high E' strings will be between 5,972.1 and 6,086.3.

4)	We cannot determine the proper interpretation of this interval.

5)	We are 95% confident that the average number of plucks to failure for all 'high E' strings tested is between 5,972.1 and 6,086.3.

In a packing plant, one of the machines packs jars into a box. A sales rep for a packing machine manufacturer comes into the plant saying that a new machine he is selling will pack the jars faster than the old machine. To test this claim, each machine is timed for how long it takes to pack 10 cartons of jars at randomly chosen times. Given a 99% confidence interval of (-6.55, -0.95) for the true difference in average times to pack the jars (old machine - new machine), what can you conclude from this interval?

Question 3 options:

1)	We are 99% confident that the average packing time of the new machine is greater than the old machine. The sales rep does not appear to be telling the truth.

2)	There is no significant difference between the average packing times of the two machines. The sales rep does not appear to be telling the truth.

3)	We are 99% confident that the average packing time of the old machine is greater than the new machine. The sales rep appears to be correct.

4)	We are 99% confident that the difference between the two sample means falls within the interval.

5)	We do not have enough information to make a conclusion.

Answer 1