Question

11) 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. 93 178 127 98 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

	x	(x-xbar)^2
	93	205.4444444
	178	4993.777778
	127	386.7777778
	98	87.11111111
	75	1045.444444
	94	177.7777778
	116	75.11111111
	100	53.77777778
	85	498.7777778
sum	966	7524
Mean(x)=xbar=sum(x)/n	107.3333
standard deviation(s)=sum(x-xbar)^2/n-1	30.66757
n	9

#mean==107.33

sample standard deviation=s=30.7

Ansb:.  90% confidence interval for the population average startup costs μ is

Mean(x)=xbar=sum(x)/n	107.3333
standard deviation(s)=sum(x-xbar)^2/n-1	30.66757
n	9
for 90 % confidence level with degree of freedom (n-1)=8
=1-c%=1-0.90=0.1	0.1
degrres of freedom	8
value of t-critical is obtain from t-table with corresponding df=8	1.859548
Margin of error =t*s/sqrt(n)	19.00927
LCL=xbar-ME	88.32406
UCL=xbar+ME	126.3426

lower limit =$ 88.3 thousand dollars

upper limit =$126.3 thousand dollars