The method of tree ring dating gave the following years A.D. for an archaeological excavation site. Assume that the population ofxvalues has an approximately normal distribution.

1,257 1,236 1,292 1,236 1,268 1,316 1,275 1,317 1,275

(a) Use a calculator with mean and standard deviation keys to find the sample mean yearxand sample standard deviations. (Round your answers to four decimal places.)

x=A.D.

s=yr

(b) Find a 90% confidence interval for the mean of all tree ring dates from this archaeological site. (Round your answers to the nearest whole number.)

lower limitA.D.

upper limitA.D.

The method of tree-ring dating gave the following years A.D. for an archaeological excavation site. Assume that the population ofxvalues has an approximately normal distribution.

1,3131,2011,2361,3131,2681,3161,2751,3171,275

(a)

Use a calculator with mean and standard deviation keys to find the sample mean yearxand sample standard deviations. (Round your answers to four decimal places.)

x=A.D.

s=yr

(b)

When finding a 90% confidence interval, what is the critical value for confidence level? (Give your answer to three decimal places.)

t_c=

What is the maximal margin of error when finding a 90% confidence interval for the mean of all tree-ring dates from this archaeological site? (Round your answer to the nearest whole number.)

E=

Find a 90% confidence interval for the mean of all tree-ring dates from this archaeological site. (Round your answers to the nearest whole number.)

lower limitA.D.

upper limitA.D.

The method of tree-ring dating gave the following years A.D. for an archaeological excavation site. Assume that the population ofxvalues has an approximately normal distribution.

1,292 1,299 1,236 1,285 1,268 1,316 1,275 1,317 1,275

(a)

Use a calculator with mean and standard deviation keys to find the sample mean yearxand sample standard deviations. (Round your answers to four decimal places.)

x=A.D.

s=yr

(b)

Find a 90% confidence interval for the mean of all tree-ring dates from this archaeological site. (Round your answers to the nearest whole number.)

lower limitA.D.

upper limitA.D.

How much do wild mountain lions weigh? Adult wild mountain lions (18 months or older) captured and released for the first time in the San Andres Mountains gave the following weights (pounds):

72 100 128 130 60 64

Assume that the population ofxvalues has an approximately normal distribution.

(a) Use a calculator with mean and sample standard deviation keys to find the sample mean weightxand sample standard deviations. (Round your answers to four decimal places.)

x=lb

s=lb

(b) Find a 75% confidence interval for the population average weightof all adult mountain lions in the specified region. (Round your answers to one decimal place.)

lower limitlb

upper limitlb

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 ofxvalues has an approximately normal distribution.

96 175 130 90 75 94 116 100 85

(a) Use a calculator with mean and sample standard deviation keys to find the sample mean startup costxand sample standard deviations. (Round your answers to four decimal places.)

x=thousand dollars

s=thousand dollars

(b) Find a 90% confidence interval for the population average startup costsfor candy store franchises. (Round your answers to one decimal place.)

lower limitthousand dollars

upper limitthousand dollars