Statistical Inference

Question 1

Alternative Hypothesis (Ha)

Answer 1

The hypothesis concluded to be true if the null hypothesis is rejected, typically that different groups have different parameters

Question 2

Census

Answer 2

Collection of data from every element in the population of interest

Question 3

Central Limit Theorem (CLT)

Answer 3

A theorem that enables one to use the normal probability distribution to approximate the sampling distribution whenever the sample size is large, approximately 30

Question 4

Confidence coefficient

Answer 4

The confidence level expressed as a decimal value

Question 5

Confidence interval; interval estimate

Answer 5

an estimate of a population parameter that provides an interval believed to contain the value of the parameter at a given confidence level, of the form point estimate ± margin of error.

Question 6

Confidence level

Answer 6

The confidence associated with an interval estimate

Question 7

Degrees of freedom

Answer 7

the number of values in the final calculation of a statistic that are free to vary; n-1 for a t distribution

Question 8

Finite population correction factor

Answer 8

The term V’(N - n)/(N - 1) that is used in the formulas for sigma whenever a finite population, rather than an infinite population, is being sampled.

Question 9

Frame

Answer 9

A listing of the elements from which the sample will be selected.

Question 10

Hypothesis testing

Answer 10

The process of making a conjecture about the value of a population parameter, collecting sample data that can be used to assess this conjecture, measuring the strength of the evidence against the conjecture that is provided by the sample, and using these results to draw a conclusion about the conjecture.

Question 11

Interval estimation

Answer 11

The process of using sample data to calculate a range of values that is believed to include the unknown value of a population parameter.

Question 12

Level of significance

Answer 12

The probability that the interval estimation procedure will generate an interval that does not contain the value of parameter being; also the probability of making a Type I error when the null hypothesis is true as an equality.

Question 13

Margin of error

Answer 13

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

Question 14

Null Hypothesis (H0)

Answer 14

The hypothesis tentatively assumed to be true in the hypothesis testing procedure, typically that there is no difference between groups

Question 15

One-tailed test

Answer 15

A hypothesis test in which rejection of the null hypothesis occurs for values of the test statistic in one tail of its sampling distribution.

Question 16

Parameter

Answer 16

A measurable factor that defines a characteristic of a population, process, or system, such as a population mean A, a population standard deviation if, a population proportion p, and so on.

Question 17

Point estimate

Answer 17

The value of a point estimator used in a particular instance as an estimate of a population parameter.

Question 18

Point estimator

Answer 18

the sample statistic when used to estimate the corresponding population parameter

Question 19

Practical significance

Answer 19

The potential impact the result of statistical inference will have on business decisions.

Question 20

p-value

Answer 20

A probability that gives a measure of the evidence against the null hypothesis provided by the sample. Smaller p values indicate more evidence against H0. For a lower-tail test, the p value is the probability of obtaining a value for the test statistic as small as or smaller than that provided by the sample. For an upper-tail test, the p value is the probability of obtaining a value for the test statistic as large as or larger than that provided by the sample. For a two-tailed test, the p value is the probability of obtaining a value for the test statistic at least as unlikely as or more unlikely than that provided by the sample.

Question 21

Random sample

Answer 21

A draw from an infinite populationsuch that the following conditions are satisfied: (1) Each element selected comes from the same population; and (2) each element is selected independently.

Question 22

Sample statistic

Answer 22

A characteristic of sample data that is used to estimate the value of the corresponding population parameter.

Question 23

sampled population

Answer 23

The population from which the sample is drawn.

Question 24

Sampling distribution

Answer 24

A probability distribution consisting of all possible values of a sample statistic.

Question 25

Sampling error

Answer 25

The difference between the value of a sample statistic and the value of the corresponding population parameter

Question 26

Simple random sample

Answer 26

A sample of size n from a finite population of size N selected such that each possible sample of size n has the same probability of being selected.

Question 27

Standard error

Answer 27

The standard deviation of a point estimator.

Question 28

standard normal distribution

Answer 28

A normal distribution with a mean of zero and standard deviation of one

Question 29

Statistical inference

Answer 29

The process of making estimates and drawing conclusions about one or more characteristics of a population (the value of one or more parameters) through the analysis of sample data drawn from the population.

Question 30

T distribution

Answer 30

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

Question 31

Test statistic

Answer 31

A statistic whose value helps determine whether a null hypothesis should be rejected.

Question 32

Target population

Answer 32

The population for which statistical inferences such as point estimates are made. It is important for the target population to correspond as closely as possible to the sampled population.

Question 33

Two-tailed test

Answer 33

A hypothesis test in which rejection of the null hypothesis occurs for values of the test statistic in either tail of its sampling distribution.

Question 34

Type I error

Answer 34

The error of rejecting H0 when it is true

Question 35

Type II error

Answer 35

The error of accepting H0 when it is false.