Chapter 8

Question 1

Confidence Coefficient

Answer 1

The confidence level expressed as a decimal value. For example, .95 is the confidence coefficient for a 95% confidence level.

Question 2

Confidence interval

Answer 2

Another name for an interval estimate.

Question 3

Confidence Level

Answer 3

The confidence associated with an interval estimate. For example, if an interval estimation procedure provides intervals such that 95% of the intervals formed using the procedure will include the population parameter, the interval estimate is said to be constructed at the 95% confidence level.

Question 4

Degrees of Freedom

Answer 4

A parameter of the t distribution. When the t distribution is used in the computation of an interval estimate of a population mean, the appropriate t distribution has n − 1 degrees of freedom, where n is the size of the sample.

Question 5

Interva Estimate

Answer 5

An estimate of a population parameter that provides an interval believed to contain the value of the parameter. For the interval estimates in this chapter, it has the form: point estimate ± margin of error.

Question 6

Level of Significance

Answer 6

The probability that the interval estimation procedure will generate an interval that does not contain

Question 7

Margin of Error

Answer 7

The ± value added to and subtracted from a point estimate in order to develop an interval estimate of a population parameter.

Question 8

Practical Significance

Answer 8

The real-world impact the result of statistical inference will have on business decisions.

Question 9

σ known

Answer 9

The case when historical data or other information provide a good value for the population standard deviation prior to taking a sample. The interval estimation procedure uses this known value of σ in computing the margin of error.

Question 10

σ unknown

Answer 10

The more common case when no good basis exists for estimating the population standard deviation prior to taking the sample. The interval estimation procedure uses the sample standard deviation s in computing the margin of error.

Question 11

t Distribution

Answer 11

A family of probability distributions that can be used to develop an interval estimate of a population mean whenever the population standard deviation σ is unknown and is estimated by the sample standard deviation s.