Question 1

The 95% confidence interval for the average weight of a product is from 72.23kg to 77.77kg.Interpret this confidence interval.

Accepted Answer

The answer of The 95% confidence interval for the average...

Question 2

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: $\bar { x }$ = 75kg and s = 10kg.
-Calculate a 90 percent confidence interval for $\mu$ 
.

Accepted Answer

The answer of The weight of a product is normally...

Question 3

A sample of 2,000 people yielded $\hat { p }$ =.52.
-What is the estimated standard deviation of the sample proportion?

Accepted Answer

The answer of A sample of 2,000 people yielded \(\hat...

Question 4

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: $\bar { x }$ = 75kg and s = 10kg.
-Calculate a 95 percent confidence interval for $\mu$ 
.

Accepted Answer

The answer of The weight of a product is normally...

Question 5

A random sample of size 10 is taken from a population assumed to be normal,and $\bar { x }$ 
= 1.2 and the variance is .36.Calculate a 99 percent confidence interval for $\mu$ 
.

Accepted Answer

The answer of A random sample of size 10 is...

Question 6

A sample of 2,000 people yielded $\hat { p }$ =.52.
-Calculate a 95 percent confidence interval for p.

Accepted Answer

The answer of A sample of 2,000 people yielded \(\hat...

Question 7

A sample of 2,000 people yielded $\hat { p }$ =.52.
-Calculate a 90 percent confidence interval for p.

Accepted Answer

The answer of A sample of 2,000 people yielded \(\hat...

Question 8

An insurance company estimates 40 percent of its claims have errors.The insurance company wants to estimate with 90 percent confidence the proportion of claims with errors.What sample size is needed if they wish to be within 5 percent of the actual?

Accepted Answer

The answer of An insurance company estimates 40 percent of...

Question 9

We want to estimate with 99 percent confidence the percentage of buyers of cars who are under 30 years of age.A margin of error of 5 percentage points is desired.What sample size is needed?

Accepted Answer

The answer of We want to estimate with 99 percent...

Question 10

The success rate of a surgical procedure is 70 per 100 cases examined in a sample.Find a 90 percent confidence interval for the total number of successes per 1,000 cases.

Accepted Answer

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

Question 11

A random sample of size 10 is taken from a population assumed to be normal,and $\bar { x }$ 
= 1.2 and s = 0.6.Calculate a 90 percent confidence interval for $\mu$ 
.

Accepted Answer

The answer of A random sample of size 10 is...

Question 12

Find a 99 percent confidence interval for $\mu$ 
if $\bar { x }$ 
= 98.6,s = 2,and n = 5.Assume that the sample is randomly selected from a normally distributed population.

Accepted Answer

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

Question 13

A cable TV company wants to estimate the percentage of people in Alberta watching a particular station during an evening hour.An approximation is 20 percent.They want the estimate to be at the 90 percent confidence level and within 2 percent of the actual proportion.What sample size is needed?

Accepted Answer

The answer of A cable TV company wants to estimate...

Question 14

In a randomly selected group of 650 automobile deaths,180 were alcohol related.Construct a 95 percent confidence interval for the true proportion of all automobile accidents caused by alcohol.

Accepted Answer

The answer of In a randomly selected group of 650...

Question 15

A random sample of size 10 is taken from a population assumed to be normal,and $\bar { x }$ 
= 1.2 and s = .6.Calculate a 95 percent confidence interval for $\mu$ 
.

Accepted Answer

The answer of A random sample of size 10 is...

Question 16

A sample of 2,000 people yielded $\hat { p }$ =.52.
-Calculate a 99 percent confidence interval for p.

Accepted Answer

The answer of A sample of 2,000 people yielded \(\hat...

Question 17

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: $\bar { x }$ = 75kg and s = 10kg.
-Calculate a 99 percent confidence interval for $\mu$ 
.

Accepted Answer

The answer of The weight of a product is normally...

Question 18

The customer service manager for the XYZ Fastener Manufacturing Company examined 60 vouchers and found nine vouchers containing errors.Find a 95 percent confidence interval for the proportion of vouchers with errors.

Accepted Answer

The answer of The customer service manager for the XYZ...

Question 19

The 99% confidence interval for the average weight of a product is from 71.36kg to 78.64kg.Interpret this confidence interval.

Accepted Answer

The answer of The 99% confidence interval for the average...

Question 20

You want to estimate the proportion of customers who are satisfied with their supermarket at α = .10 to within .025 of the true value.It has been estimated that p =.85.How large of a sample is needed?

Accepted Answer

The answer of You want to estimate the proportion of...

Quiz 9: Statistical Inferences Based on Two Samples

The 95% confidence interval for the average weight of a product is from 72.23kg to 77.77kg.Interpret this confidence interval.

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: xˉ\bar { x }xˉ = 75kg and s = 10kg. -Calculate a 90 percent confidence interval for μ\muμ .

A sample of 2,000 people yielded p^\hat { p }p^​ =.52. -What is the estimated standard deviation of the sample proportion?

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: xˉ\bar { x }xˉ = 75kg and s = 10kg. -Calculate a 95 percent confidence interval for μ\muμ .

A random sample of size 10 is taken from a population assumed to be normal,and xˉ\bar { x }xˉ = 1.2 and the variance is .36.Calculate a 99 percent confidence interval for μ\muμ .

A sample of 2,000 people yielded p^\hat { p }p^​ =.52. -Calculate a 95 percent confidence interval for p.

A sample of 2,000 people yielded p^\hat { p }p^​ =.52. -Calculate a 90 percent confidence interval for p.

An insurance company estimates 40 percent of its claims have errors.The insurance company wants to estimate with 90 percent confidence the proportion of claims with errors.What sample size is needed if they wish to be within 5 percent of the actual?

We want to estimate with 99 percent confidence the percentage of buyers of cars who are under 30 years of age.A margin of error of 5 percentage points is desired.What sample size is needed?

The success rate of a surgical procedure is 70 per 100 cases examined in a sample.Find a 90 percent confidence interval for the total number of successes per 1,000 cases.

A random sample of size 10 is taken from a population assumed to be normal,and xˉ\bar { x }xˉ = 1.2 and s = 0.6.Calculate a 90 percent confidence interval for μ\muμ .

Find a 99 percent confidence interval for μ\muμ if xˉ\bar { x }xˉ = 98.6,s = 2,and n = 5.Assume that the sample is randomly selected from a normally distributed population.

A cable TV company wants to estimate the percentage of people in Alberta watching a particular station during an evening hour.An approximation is 20 percent.They want the estimate to be at the 90 percent confidence level and within 2 percent of the actual proportion.What sample size is needed?

In a randomly selected group of 650 automobile deaths,180 were alcohol related.Construct a 95 percent confidence interval for the true proportion of all automobile accidents caused by alcohol.

A random sample of size 10 is taken from a population assumed to be normal,and xˉ\bar { x }xˉ = 1.2 and s = .6.Calculate a 95 percent confidence interval for μ\muμ .

A sample of 2,000 people yielded p^\hat { p }p^​ =.52. -Calculate a 99 percent confidence interval for p.

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: xˉ\bar { x }xˉ = 75kg and s = 10kg. -Calculate a 99 percent confidence interval for μ\muμ .

The customer service manager for the XYZ Fastener Manufacturing Company examined 60 vouchers and found nine vouchers containing errors.Find a 95 percent confidence interval for the proportion of vouchers with errors.

The 99% confidence interval for the average weight of a product is from 71.36kg to 78.64kg.Interpret this confidence interval.

You want to estimate the proportion of customers who are satisfied with their supermarket at α = .10 to within .025 of the true value.It has been estimated that p =.85.How large of a sample is needed?

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: $\bar { x }$ = 75kg and s = 10kg. -Calculate a 90 percent confidence interval for $\mu$ .

A sample of 2,000 people yielded $\hat { p }$ =.52. -What is the estimated standard deviation of the sample proportion?

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: $\bar { x }$ = 75kg and s = 10kg. -Calculate a 95 percent confidence interval for $\mu$ .

A random sample of size 10 is taken from a population assumed to be normal,and $\bar { x }$ = 1.2 and the variance is .36.Calculate a 99 percent confidence interval for $\mu$ .

A sample of 2,000 people yielded $\hat { p }$ =.52. -Calculate a 95 percent confidence interval for p.

A sample of 2,000 people yielded $\hat { p }$ =.52. -Calculate a 90 percent confidence interval for p.

A random sample of size 10 is taken from a population assumed to be normal,and $\bar { x }$ = 1.2 and s = 0.6.Calculate a 90 percent confidence interval for $\mu$ .

Find a 99 percent confidence interval for $\mu$ if $\bar { x }$ = 98.6,s = 2,and n = 5.Assume that the sample is randomly selected from a normally distributed population.

A random sample of size 10 is taken from a population assumed to be normal,and $\bar { x }$ = 1.2 and s = .6.Calculate a 95 percent confidence interval for $\mu$ .

A sample of 2,000 people yielded $\hat { p }$ =.52. -Calculate a 99 percent confidence interval for p.

The weight of a product is normally distributed.A sample of 50 units is taken from a batch.The sample yielded the following results: $\bar { x }$ = 75kg and s = 10kg. -Calculate a 99 percent confidence interval for $\mu$ .