Statistics Exam 2, oops

Question 1

Hypothesis Testing

Answer 1

Compares data to what we would expect to see if a specific H0 were true.

Question 2

Null Hypothesis

Answer 2

Specific statement about a population parameter made for the purposes of argument.

Question 3

Alternative Hypothesis

Answer 3

Includes all other feasible values for the population parameter besides the value stated in the null hypothesis.

Question 4

Two-Sided/Tailed Test

Answer 4

The Ha includes parameter values on both sides of the parameter value specified by the H0.

Question 5

Test Statistic

Answer 5

A number calculated from the data that is used to evaluate how compatible the data are with the result expected under H0.

Question 6

Null Distribution

Answer 6

Sampling distribution of outcomes for a test statistic under the assumption that the H0 is true.

Question 7

P-Value

Answer 7

The probability of obtaining the data (or data showing as great or greater difference from H0) if the H0 were true.

Question 8

Significance Level

Answer 8

Probability used as a criterion for rejecting the H0.

Question 9

Type I Error

Answer 9

Rejecting a true null hypothesis. Moving alpha to a smaller magnitude can reduce the chance of it happening.

Question 10

Type II Error

Answer 10

Failing to reject a false null hypothesis. A larger sample size can decrease the chance of it happening.

Question 11

Power

Answer 11

The probability that a random sample will lead to rejection of a false null hypothesis. A low probability of a TII Error is said to have high power.

Question 12

Binomial Distribution

Answer 12

Provides the probability distribution for the number of “successes” in a fixed number of independent trials, when the probability of success is the same in each trial.

Question 13

Binomial Test

Answer 13

Uses data to test whether a population proportion matches a null expectation for the proportion.

Question 14

Proportional Model

Answer 14

Frequency of occurrence of events is proportional to the number of opportunities.

Question 15

X2 Goodness-of-Fit Test

Answer 15

Compares frequency data to a probability model stated by the null hypothesis.

Question 16

X2 Test Statistic

Answer 16

Measures discrepancy between observed frequencies from the data and expected frequencies from the null hypothesis.

Question 17

Degrees of Freedom

Answer 17

Specifies which X2 distribution to use as the null distribution.

Question 18

Critical Value

Answer 18

Value of a test statistic that marks the boundary of a specified area in the tail of a sampling distribution under H0.

Question 19

Poisson Distribution

Answer 19

Describes the number of successes in blocks of time or space, when successes happen independently of each other and occur with equal probability at every instant in time or point in space.

Question 20

Continency Analysis

Answer 20

Estimates and tests for an association between two or more categorical variables.

Question 21

Relative Risk

Answer 21

Probability of an undesired outcome in the treatment group divided by the Pr of the same outcome in a control group.

Question 22

Odds

Answer 22

Pr of success divided by Pr of failure.

Question 23

Odds Ratio

Answer 23

Odds of success in one group divided by the odds of success in a second group.

Question 24

Fischer’s Exact Test

Answer 24

Examines the independence of two categorical variables, even with small expected values.