Question 1

A sample of 100 items has a standard deviation of 5.1 and a mean of 21.6.Construct a 95 percent confidence interval for $\mu$ 
.

Accepted Answer

The answer of A sample of 100 items has a...

Question 2

A sample of 12 items yields an average weight of $\bar { x }$ 
= 48.5 grams and a standard deviation of s = 1.5 grams.Assuming weights follow a normal distribution,construct a 90 percent confidence interval for the population mean weight.

Accepted Answer

The answer of A sample of 12 items yields an...

Question 3

Given the following test scores,find a 95 percent confidence interval for the population mean: 148,154,158,160,161,162,166,170,182,195,236.Assume population normality.

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The answer of Given the following test scores,find a 95...

Question 4

What sample size is needed to estimate with 95 percent confidence the mean intake of calcium within 20 units of the true mean if the intake is normal with a variance of 1900 units?

Accepted Answer

The answer of What sample size is needed to estimate...

Question 5

Of a random sample of 600 trucks at a bridge,114 had bad signal lights.Construct a 95 percent confidence interval for the percentage of trucks that had bad signal lights.

Accepted Answer

The answer of Of a random sample of 600 trucks...

Question 6

In a study of 265 subjects,the average score on the examination was 63.8 and s = 3.08.What is a 95 percent confidence for $\mu$ 
? Assume scores are normally distributed.

Accepted Answer

The answer of In a study of 265 subjects,the average...

Question 7

The success rate of a procedure is 37 per 120 cases in a sample.Find a 95 percent confidence interval for the actual success proportion of the procedure.

Accepted Answer

The answer of The success rate of a procedure is...

Question 8

What sample size is needed to obtain a 90 percent confidence interval for the mean protein content of meat if the estimate is to be within 2 grams of the true mean value? Assume that the variance is 49 grams.

Accepted Answer

The answer of What sample size is needed to obtain...

Question 9

Find a 99 percent confidence interval for p when $\hat { p }$ 
= .51 and n = 1,000.

Accepted Answer

The answer of Find a 99 percent confidence interval for...

Question 10

Ten items of 100 are defective.Develop a 95 percent confidence interval for the population proportion of defectives.

Accepted Answer

The answer of Ten items of 100 are defective.Develop a...

Question 11

In a survey of 1,000 people,420 are opposed to the tax increase.Construct a 95 percent confidence interval for the proportion of those people opposed to the tax increase.

Accepted Answer

The answer of In a survey of 1,000 people,420 are...

Question 12

Find a 95 percent confidence interval for p when $\hat { p }$ 
=.25 and n = 400.

Accepted Answer

The answer of Find a 95 percent confidence interval for...

Question 13

A sample of 8 items has an average fat content of 18.6 grams and a standard deviation of 2.4 grams.Assuming fat content has a normal distribution,construct a 99 percent confidence interval for $\mu$ 
.

Accepted Answer

The answer of A sample of 8 items has an...

Question 14

Find the 99 percent confidence interval for p when $\hat { p }$ 
= 0.2,and n = 100.

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The answer of Find the 99 percent confidence interval for...

Question 15

In a survey of 400 people,60 percent favour new zoning laws.Find a 95 percent confidence interval for the true proportion favouring new laws.

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The answer of In a survey of 400 people,60 percent...

Question 16

What is a 95 percent confidence interval for $\mu$ 
when n = 10, $\bar { x }$ 
= 34.1,and s = 3.0? Assume population normality.

Accepted Answer

The answer of What is a 95 percent confidence interval...

Question 17

What sample size is needed to obtain a 95 percent confidence interval for the proportion of fat in meat that is within 2 percent of the true value?

Accepted Answer

The answer of What sample size is needed to obtain...

Question 18

What sample size is needed to estimate the proportion of highway speeders within 5 percent using a 90 percent confidence level?

Accepted Answer

The answer of What sample size is needed to estimate...

Question 19

A sample of 200 observations is taken.The mean is 31.7 and the standard deviation is 1.8.Assuming measurements follow a normal distribution,find a 90 percent confidence interval for the population mean.

Accepted Answer

The answer of A sample of 200 observations is taken.The...

Question 20

What is a 95 percent confidence interval for $\mu$ 
when n = 10, $\bar { x }$ 
= 35.6,and s = 13.0? Assume population normality.

Accepted Answer

The answer of What is a 95 percent confidence interval...

Quiz 9: Statistical Inferences Based on Two Samples

A sample of 100 items has a standard deviation of 5.1 and a mean of 21.6.Construct a 95 percent confidence interval for μ\muμ .

A sample of 12 items yields an average weight of xˉ\bar { x }xˉ = 48.5 grams and a standard deviation of s = 1.5 grams.Assuming weights follow a normal distribution,construct a 90 percent confidence interval for the population mean weight.

Given the following test scores,find a 95 percent confidence interval for the population mean: 148,154,158,160,161,162,166,170,182,195,236.Assume population normality.

What sample size is needed to estimate with 95 percent confidence the mean intake of calcium within 20 units of the true mean if the intake is normal with a variance of 1900 units?

Of a random sample of 600 trucks at a bridge,114 had bad signal lights.Construct a 95 percent confidence interval for the percentage of trucks that had bad signal lights.

In a study of 265 subjects,the average score on the examination was 63.8 and s = 3.08.What is a 95 percent confidence for μ\muμ ? Assume scores are normally distributed.

The success rate of a procedure is 37 per 120 cases in a sample.Find a 95 percent confidence interval for the actual success proportion of the procedure.

What sample size is needed to obtain a 90 percent confidence interval for the mean protein content of meat if the estimate is to be within 2 grams of the true mean value? Assume that the variance is 49 grams.

Find a 99 percent confidence interval for p when p^\hat { p }p^​ = .51 and n = 1,000.

Ten items of 100 are defective.Develop a 95 percent confidence interval for the population proportion of defectives.

In a survey of 1,000 people,420 are opposed to the tax increase.Construct a 95 percent confidence interval for the proportion of those people opposed to the tax increase.

Find a 95 percent confidence interval for p when p^\hat { p }p^​ =.25 and n = 400.

A sample of 8 items has an average fat content of 18.6 grams and a standard deviation of 2.4 grams.Assuming fat content has a normal distribution,construct a 99 percent confidence interval for μ\muμ .

Find the 99 percent confidence interval for p when p^\hat { p }p^​ = 0.2,and n = 100.

In a survey of 400 people,60 percent favour new zoning laws.Find a 95 percent confidence interval for the true proportion favouring new laws.

What is a 95 percent confidence interval for μ\muμ when n = 10, xˉ\bar { x }xˉ = 34.1,and s = 3.0? Assume population normality.

What sample size is needed to obtain a 95 percent confidence interval for the proportion of fat in meat that is within 2 percent of the true value?

What sample size is needed to estimate the proportion of highway speeders within 5 percent using a 90 percent confidence level?

A sample of 200 observations is taken.The mean is 31.7 and the standard deviation is 1.8.Assuming measurements follow a normal distribution,find a 90 percent confidence interval for the population mean.

What is a 95 percent confidence interval for μ\muμ when n = 10, xˉ\bar { x }xˉ = 35.6,and s = 13.0? Assume population normality.

A sample of 100 items has a standard deviation of 5.1 and a mean of 21.6.Construct a 95 percent confidence interval for $\mu$ .

A sample of 12 items yields an average weight of $\bar { x }$ = 48.5 grams and a standard deviation of s = 1.5 grams.Assuming weights follow a normal distribution,construct a 90 percent confidence interval for the population mean weight.

In a study of 265 subjects,the average score on the examination was 63.8 and s = 3.08.What is a 95 percent confidence for $\mu$ ? Assume scores are normally distributed.

Find a 99 percent confidence interval for p when $\hat { p }$ = .51 and n = 1,000.

Find a 95 percent confidence interval for p when $\hat { p }$ =.25 and n = 400.

A sample of 8 items has an average fat content of 18.6 grams and a standard deviation of 2.4 grams.Assuming fat content has a normal distribution,construct a 99 percent confidence interval for $\mu$ .

Find the 99 percent confidence interval for p when $\hat { p }$ = 0.2,and n = 100.

What is a 95 percent confidence interval for $\mu$ when n = 10, $\bar { x }$ = 34.1,and s = 3.0? Assume population normality.

What is a 95 percent confidence interval for $\mu$ when n = 10, $\bar { x }$ = 35.6,and s = 13.0? Assume population normality.