Question

Do you want to own your own candy store? Wow! With some interest in running your own business and a decent credit rating, you can probably get a bank loan on startup costs for franchises such as Candy Express, The Fudge Company, Karmel Corn, and Rocky Mountain Chocolate Factory. Startup costs (in thousands of dollars) for a random sample of candy stores are given below. Assume that the population of x values has an approximately normal distribution. 94 172 127 90 75 94 116 100 85

(a) Use a calculator with mean and sample standard deviation keys to find the sample mean startup cost x and sample standard deviation s. (Round your answers to one decimal place.) x = thousand dollars s = thousand dollars

(b) Find a 90% confidence interval for the population average startup costs μ for candy store franchises. (Round your answers to one decimal place.) lower limit thousand dollars upper limit thousand dollars

Answer 1

Given data set is

94 172 127 90 75 94 116 100 85

We will use TI 84 calculator to solve the question

(A) enter the data set in L1 list

then press stat then calc and select 1 var stats

select L1 as the required data set and press on calculate, we get

x(bar) = 105.9

s = 29.3

(b) using the data calculated in part (a) to find the confidence interval

press stat then tests then TInterval

enter the data

xbar = 105.9

s = 29.3

n = 9

c-level = 0.90

click on calculate, we get

lower limit = 87.7

upper limit = 124.1