Chap 7 Statistical Tests Flashcards Preview

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Flashcards in Chap 7 Statistical Tests Deck (32):
1

Alpha Level

The a priori probability of falsely rejecting the null hypothesis that the researcher is willing to accept. It is used, in conjunction with the p value, to determine whether a sample statistic is statistically significant

2

Alternative Hypothesis

The alternative null hypothesis. Usually, it is the hypothesis that there is some effect present in the population ( e.g. two population means are not equal, two variables are correlated, a sample mean is diff. from a population mean, etc.).

3

Confidence Interval

A interval calculated using sample statistics to contain the population parameter, within a certain degree of confidence ( e.g. 95% confidence)

4

Descriptive Statistic

Statistics that describe that statistics of a given sample or population. These statistics are only meant to describe the characteristics of those from whom data were collected

5

Effect Size`

A measure of the size of the effect observed in some statistic. It is a way of determining the practical significance of a statistic by reducing the impact of sample size.

6

Inferential Statistic

Stats generated from a sample data that are used to make inferences about the characteristics of the population the sample is alleged to represent.

7

Null Hypothesis

The hypothesis that there is no effect in the population
( e.g. that two population means are not different from each other, that 2 variables are not correlated in the population)

8

One-Tailed

A test of statistical significance that is conducted just for one tail of the distribution. (e.g. that the sample mean will be larger than the population mean)

9

Population

The group from which data is collected or a sample is selected. The population encompasses the entire group for which the data are alleged to apply.

10

Practical Significance

A judgement about whether a statistic is relevant or of any importance, in the real world.

11

p value

The probability of obtaining a statistic of a given size from a sample of a given size by chance, or due to random error.

12

Random Chance

The probability of a statistical event occurring due simply to random variations in the characteristics of the samples of a given size selected randomly from a population.

13

Random Sampling Error

The error, or variation, associated with randomly selecting samples of a given size from a population.

14

Sample

An individual or group, selected from a population, from whom of which data are collected.

15

Statistical Significance

When the probability of obtaining a statistic of a given size due strictly to random sampling error, or chance, is less than the selected alpha level, the result is said to be statistically. It also represents a rejection of the null hypothesis.

16

Two-Tailed

A test of statistical significance that is conducted just for both tails of the distribution. (e.g. that the sample mean will be different from the population mean).

17

Type 1 Error

Rejecting the null hypothesis when in fact the null hypothesis is true.

18

p value

The p value, or the probability

19

The alpha level 0.5

20

d

One measure of effect size

21

S

Standard deviation used in the effect size formula

22

Infinity

23

sx ̅

The standard error calculated with the sample standard deviation

24

ox ̅

The standard error calculated with the population standard deviation

25

Ho

The null hypothesis

26

HA or H1

The alternative hypothesis

27

Point Estimate

Point estimate provides a single plausible value for a parameter

28

Confidence Interval

A plausible range of values for the population parameter

Note: confidence intervals only attempt to capture population parameters.

29

Central limit Theorem

The fact that a sample size increases, the sampling distribution of the mean becomes increasingly normal, regardless of the shape of the distribution of the sample

30

In a confidence interval a Margin of Error looks like what?

z* x SE

31

Type 2 Error

Failing to reject the null hypothesis when the alternative is true.

32

what is the significance level

5% OR ∝ = 0.05