The branch manager of an outlet (Store 1) of a nationwide chain of pet supply stores wants to study characteristics of her customers. In particular, she decides to focus on two variables: the amount of money spent by customers and whether the customers own only one dog, only one cat, or more than one dog and/or cat. The results from a sample of 70 customers are follows:

Question

- Amount of money spent: X = $21.34, S=$9.22
- 37 customers own only a dog
- 26 customers own only a cat
- 7 customers own more than one dog and/or cat

a) Construct a 95% confidence interval estimate of the population mean amount in the pet supply.
b) Construct a 90% confidence interval estimate of the population proportion of customers who own only a cat

The branch manager of another outlet (Store 2) wishes to conduct a similar survey in the store. The manager does not have access to the information generated by the manager of Store 1. Answer the following questions:

c) What sample size is needed to have 95% confidence of estimating the population mean amount spent in his store within +/-$1.50 if the standard deviation is $10
d) What sample size is needed to have 90% confidence of estimating the population proportion of customers who own only a cat to within +/-0.045?
e) Based on your answers for c and d, how large a sample should the manager take?

Note*The manager at store 2 only has enough money budgeted to do one sample analysis

Answer 1

- Amount of money spent: X = $21.34, S=$9.22
- 37 customers own only a dog
- 26 customers own only a cat
- 7 customers own more than one dog and/or cat

a) Construct a 95% confidence interval estimate of the population mean amount in the pet supply.
b) Construct a 90% confidence interval estimate of the population proportion of customers who own only a cat

Answer 2

The branch manager of another outlet (Store 2) wishes to conduct a similar survey in the store. The manager does not have access to the information generated by the manager of Store 1. Answer the following questions:

c) What sample size is needed to have 95% confidence of estimating the population mean amount spent in his store within +/-$1.50 if the standard deviation is $10
d) What sample size is needed to have 90% confidence of estimating the population proportion of customers who own only a cat to within +/-0.045?
e) Based on your answers for c and d, how large a sample should the manager take?

Note: The manager at store 2 only has enough money budgeted to do one sample analysis.

Answer 3

Incomplete post

Answer 4

For complete post, please see Statistics help with Statistics help Part 2 and Part 3