Chapter 9 - Evaluating Hypotheses Flashcards
What are descriptive statistics?
The science of describing distributions of samples of populations.
What are inferential statistics?
The science of using sample statistics to make inferences or decisions about population parameters.
What is a hypothesis?
An assumption or inference about a parameter or distribution that can be tested.
What is a null hypothesis?
The hypothesis that there is no effect or no difference.
What is an alternative hypothesis?
The hypothesis that there is in fact an effect or a difference.
What are the symbols for null hypothesis?
Ho (small o)
What are the symbols for alternative hypothesis?
H1 (small 1)
What is a test statistic?
A statistic specifically designed to facilitate the making of inferences.
What is a directional (one-tailed) alternative hypothesis?
Where one direction of change (an increase or a decrease based on prior empirical research) is specified in advance.
What is a non-directional (two-tailed) alternative hypothesis?
Where the hypothesized change can be either an increase or a decrease.
What is a Type 1 error?
Rejecting the null hypothesis when it is in fact true.
What is a Type 2 error?
Failing to reject the null hypothesis when it is in fact false.
What is the level of significance?
The probability (signified by Greek a) of making a Type 1 error.
What does the Greek ‘a’ signify?
The probability of making a Type 1 error (also called “the level of significance”)
What is statistically significant?
Leading to the rejection of the null hypothesis.
What is power?
The probability of rejecting the null hypothesis when the null hypothesis is in fact false.
What does the Greek ‘B’ signify?
The probability of making a Type II error.
What is practical significance?
The degree to which a result is important. Measures whether the result is important.
What is effect size?
A measure of the magnitude of a result.
What is statistical significance?
Ensures that the result is not merely a chance fluctuation.
What is the general formula for the test statistic?
sample statistic minus population parameter divided by the standard error of the sample statistic.
What is a sample statistic?
The statistic that point-estimates the parameter of interest.
What is the observed value of the test statistic?
The value of a test statistic computed from the sample.
What is the procedure for hypothesis evaluation?
- State the null and alternative hypothesis.
- Set the criterion for rejecting Ho (null hypothesis).
- Collect a sample and compute the observed values of the sample statistic and the test statistic.
- Interpret the results.
Sample statistic
A number that can be calculated from sample data.
Population parameter
A number describing a population.
