The z value for a 97.8 confidence interval estimation is

Question 1
1.

For the interval estimation of μ when σ is known and the sample is large, the proper distribution to use is

the normal distribution

the t distribution with n degrees of freedom

the t distribution with n + 1 degrees of freedom

the t distribution with n + 2 degrees of freedom

Question 2
1.

An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the

confidence level

interval estimate

parameter value

population estimate

Question 3
1.

The value added and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the

confidence level

margin of error

parameter estimate

interval estimate

Question 4
1.

Whenever the population standard deviation is unknown and the population has a normal or near-normal distribution, which distribution is used in developing an interval estimation?

standard distribution

z distribution

alpha distribution

t distribution

Question 5
1.

The z value for a 97.8% confidence interval estimation is

2.02

1.96

2.00

2.29

Question 6
1.

The t value for a 95% confidence interval estimation with 24 degrees of freedom is

1.711

2.064

2.492

2.069

Question 7
1.

As the sample size increases, the margin of error

increases

decreases

stays the same

increases or decreases depending on the size of the mean

Question 8
1.

The ability of an interval estimate to contain the value of the population parameter is described by the

confidence level

degrees of freedom

precise value of the population mean μ

degrees of freedom minus 1

Question 9
1.

In general, higher confidence levels provide

wider confidence intervals

narrower confidence intervals

a smaller standard error

unbiased estimates

Question 10
1.

An interval estimate is a range of values used to estimate

the shape of the population's distribution

the sampling distribution

a sample statistic

a population parameter

Question 11
1.

As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution

becomes larger

becomes smaller

stays the same

becomes negative

Question 12
1.

In order to determine an interval for the mean of a population with unknown standard deviation a sample of 61 items is selected. The mean of the sample is determined to be 23. The number of degrees of freedom for reading the t value is

22

23

60

61

Question 13
1.

After computing a confidence interval, the user believes the results are meaningless because the width of the interval is too large. Which one of the following is the best recommendation?

Increase the level of confidence for the interval.

Decrease the sample size.

Increase the sample size.

Reduce the population variance.

Question 14
1.

A sample of 225 elements from a population with a standard deviation of 75 is selected. The sample mean is 180.The 95% confidence interval for μ is

105.0 to 225.0

175.0 to 185.0

100.0 to 200.0

170.2 to 189.8

Question 15
1.

The sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 is

10

11

116

117

W5 Quiz

QUESTION 1

1.

For the interval estimation of ì when ó is known and the sample is large, the

proper distribution to use is

the normal distribution

the t distribution with n degrees of freedom

the t distribution with n + 1 degrees of freedom

the t distribution with n + 2 degrees of freedom

QUESTION 2

1.

An estimate of a population parameter that provides an interval of values

believed to contain the value of the parameter is known as the

confidenc

e level

interval estimate

parameter value

population estimate

QUESTION 3

1.

The value added and subtracted from a point estimate in order to develop an

interval estimate of the population parameter is known as the

W5 Quiz

QUESTION 1

1.

For the interval estimation of μ when σ is known and the sample is large, the

proper distribution to use is

the normal distribution

the t distribution with n degrees of freedom

the t distribution with n + 1 degrees of freedom

the t distribution with n + 2 degrees of freedom

QUESTION 2

1.

An estimate of a population parameter that provides an interval of values

believed to contain the value of the parameter is known as the

confidence level

interval estimate

parameter value

population estimate

QUESTION 3

1.

The value added and subtracted from a point estimate in order to develop an

interval estimate of the population parameter is known as the