a. You measure 40 textbooks' weights, and find they have a mean weight of 63 ounces. Assume the population standard deviation is 10.9 ounces. Based on this, construct a 90% confidence interval for the true population mean textbook weight.

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b. Out of 200 people sampled, 60 had kids. Based on this, construct a 90% confidence interval for the true population proportion of people with kids.

< p <

c. A political candidate has asked you to conduct a poll to determine what percentage of people support her.

If the candidate only wants a 6% margin of error at a 99% confidence level, what size of sample is needed?

Give your answer in whole people.

d. A particular professor has noticed that the number of people,P, who complain about his attitude is dependent on the number of cups of coffee,n, he drinks. From eight days of tracking he compiled the following data:

People (P)1111955331Cups of coffee (n)11234455

Unless otherwise stated, you can round values to two decimal places.

a) Using regression to find a linear equation forP(n)

P(n)

=

b) Find the correlation coefficient

r=

c) Does the correlation coefficient indicate a strong linear trend, a weak linear trend, or no linear trend?

• strong linear trend
• weak linear trend
• no linear trend

d) Interpret the meaning of the slope of your formula in the context of the problem

e) Interpret the meaning of thePintercept in the context of the problem

f) Use your model to predict the number of people that will complain about his attitude if he drinks 8 cups of coffee.

g) Is the answer to part f reasonable? Why or why not?

h) How many cups of coffee should he drink so that no one will complain about his attitude? It is ok to round to one decimal place.