Question 1 (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 8 customers and find that the average dollar amount
spent per transaction per customer is $106.745 with a standard
deviation of $13.7164. Create a 95% confidence interval for the
true average spent for all customers per transaction.
Question 1 options:
Question 2 (1 point)
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 59
'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 6,810.9 with a standard
deviation of 152.04. A 90% confidence interval for the average
number of plucks to failure is (6,777.8, 6,844). From the option
listed below, what is the appropriate interpretation of this
interval?
Question 2 options:

1)

We are 90% confident that the average number of plucks to
failure for all 'high E' strings is between 6,777.8 and 6,844. 


2)

We are certain that 90% of the average number of plucks to
failure for all 'high E' strings will be between 6,777.8 and
6,844. 


3)

We cannot determine the proper interpretation of this
interval. 


4)

We are 90% confident that the average number of plucks to
failure for all 'high E' strings tested is between 6,777.8 and
6,844. 


5)

We are 90% confident that the proportion of all 'high E' guitar
strings fail with a rate between 6,777.8 and 6,844. 

Question 3 (1 point)
A pharmaceutical company is testing a new drug to increase
memorization ability. It takes a sample of individuals and splits
them randomly into two groups. One group is administered the drug,
and the other is given a placebo. After the drug regimen is
completed, all members of the study are given a test for
memorization ability with higher scores representing a better
ability to memorize. You are presented a 90% confidence interval
for the difference in population mean scores (with drug  without
drug) of (8.63, 6.33). What can you conclude from this
interval?
Question 3 options:

1)

We are 90% confident that the average memorization ability of
those not on the drug is higher than those who are on the
drug. 


2)

We do not have enough information to make a conclusion. 


3)

There is no significant difference between the average
memorization abilities for those on the drug compared to those not
on the drug. 


4)

We are 90% confident that the difference between the two sample
means falls within the interval. 


5)

We are 90% confident that the average memorization ability of
those on the drug is higher than those who are not on the
drug. 

Question 4 (1 point)
A restaurant wants to test a new instore marketing scheme in a
small number of stores before rolling it out nationwide. The new ad
promotes a premium drink that they want to increase the sales of.
18 locations are chosen at random and the number of drinks sold are
recorded for 2 months before the new ad campaign and 2 months
after. The average difference in nationwide sales quantity before
the ad campaign to after (after  before) is 3.7 with a standard
deviation of 9.01. Using this information, they calculate a 90%
confidence pairedt interval of (0.01, 7.39). Which of the
following is the best interpretation?
Question 4 options:

1)

We are 90% confident that the difference between the average
sales after the ad campaign and the average sales before the ad
campaign is between 0.01 and 7.39. 


2)

We are certain the average difference in sales quantity between
after the ad campaign to before for all stores is between 0.01 and
7.39. 


3)

The proportion of all stores that had a difference in sales
between after the ad campaign to before is 90%. 


4)

We are 90% confident that the average difference in the sales
quantity after to before of the stores sampled is between 0.01 and
7.39. 


5)

We are 90% confident that the average difference in sales
quantity between after the ad campaign to before for all
restaurants is between 0.01 and 7.39. 
