Question

Question 3 (1 point)

You own a small storefront retail business and are interested in determining the average amount of money a typical customer spends per visit to your store. You take a random sample over the course of a month for 42 customers and find that the average dollar amount spent per transaction per customer is $89.687 with a standard deviation of $10.9431. When creating a 99% confidence interval for the true average dollar amount spend per customer, what is the margin of error?

Question 3 options:

1)

4.5558

2)

0.8389

3)

4.5611

4)

1.6886

5)

4.0877

Question 4 (1 point)

The owner of a local golf course wanted to determine the average age (in years) of the golfers that played on the course. In a random sample of 27 golfers that visited his course, the sample mean was 47 years old and the standard deviation was 5.11 years. Using this information, the owner calculated the confidence interval of (45.3, 48.7) with a confidence level of 90% for the average age. Which of the following is an appropriate interpretation of this confidence interval?

Question 4 options:

1)	We are certain that 90% of the average ages of all golfers will be between 45.3 and 48.7 years old.

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

3)	We are 90% confident that the average age of the golfers surveyed is between 45.3 and 48.7 years old.

4)	We are 90% confident that the proportion of the ages of all golfers is between 45.3 and 48.7 years old.

5)	We are 90% confident that the average age of all golfers that play on the golf course is between 45.3 and 48.7 years old.

Answer 1

Question 3) Given that, sample size ( n ) = 42

sample mean ( M ) = $89.687

sample standard deviation ( s ) = $10.9431

t-critical value at signigicance level = 0.01 with degrees of freedom = 42 - 1 = 41 is,

Margin of error ( E ) is,

The margin of error is 4.5611

Question 4) Given that, 90% confidence interval is, (45.3, 48.7)

Interpretation: We are 90% confident that the average age of all golfers that play on the golf course is between 45.3 and 48.7 years old.