Math 117 Ch. 1 The Language of Statistical Decision Making Flashcards
Define sample
The part of the population that is actually used to get information.
Define population
The group of objects or individuals under study
Define statistical inference
The process of drawing conclusions about the population based on information from a sample of that population.
Define null hypothesis
The conventional belief, status quo or prevailing viewpoint about a population.
Define alternative hypothesis
An alternative to the null hypothesis — the statement that there is an effect, a difference, a change in the population.
Define statistically significant
The data collected are said to be statistically significant if they are very unlikely to be observed under the assumption that the null hypothesis is true. If the data are statistically significant, the our decision would be to reject the null hypothesis.
Define Type I error
Rejecting the null hypothesis when it is, in fact, true.
Define Type II error
Failing to reject the null hypothesis when it is, in fact, false.
Define significance level
A number (alpha) that represents the chance (probability) of committing a Type I error - that is, the chance of rejecting the null hypothesis when it is, in fact, true.
Define power of the test
Define as 1- B (beta). The power of the test is the chance of rejecting the null hypothesis when the alternative hypothesis is true.
Define decision rule
A formal rule that states, based on the data obtained, when to reject the null hypothesis. Generally, it specifies a set of values based on the data to be collected, which are contradictory to the null hypothesis and which favor the alternative hypothesis.
Define direction of the extreme
The position of the values that are more likely under the alternative hypothesis than under the null hypothesis.
If the larger values are more likely under H1 than H0, then the direction of the extreme is said to be to the right.
