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Angela

@angeli00

Explorer

Posted: 18 years ago

Ok guys,
I don't know we are allowed to ask for help for h/w in any section in IF, but I really need help w/stats, please. I have 2 problems, and I am stuck on it, as I don't like stats and don't understand. Please help

Here is the info-friends, if you help me, I would deeply appreciate your help and May God Bless you and Thanks:)

1. The manager of a pet supply store wants to study characteristics of customers of her store. The results from a sample of 70 customers are as follows:

Amount of money spent: X-bar = $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. Set up a 95% confidence interval estimate of the population mean amount spent in the pet supply store

b. Set up a 90% confidence interval estimate of the population proportion of customers who own only a cat.

c. The branch manager at another location would like to conduct a similar study and does not have access to the information from the first store. If he wants to have 95% confidence of estimating the true population mean amount spent in his store to within $1.50 and the standard deviation is assumed to be $10, what sample size is needed?

d. He uses the sample size specified in part c. and conducts a survey. He learns that the X-bar = $23.50; s = $10.22. Set up a 95% confidence interval estimate of the population mean amount spent in the pet supply store.

2. The following data represent the amount of soft drink filled in a sample of 50 consecutive 2-liter bottles. The results listed horizontally in the order being filled were:

2.109	2.031	2.012	1.994	1.963
2.086	2.029	2.012	1.986	1.957
2.066	2.025	2.012	1.984	1.951
2.075	2.029	2.01	1.981	1.951
2.065	2.023	2.005	1.973	1.947
2.057	2.02	2.003	1.975	1.941
2.052	2.015	1.999	1.971	1.941
2.044	2.014	1.996	1.969	1.938
2.036	2.013	1.997	1.966	1.908
2.038	2.014	1.992	1.967	1.894

a. At the 0.05 level of significance, is there evidence that the mean amount of soft drink filled is different from 2.0 liters? (complete all steps of a hypothesis test)

b. Determine the p-value and interpret its meaning.

c. In order for the test performed in (a) to be valid, the data are assumed to be normally distributed. Evaluate the assumption that assumption graphically. Are the results obtained in (a) valid? Why?