Chap 6 Standard Errors Flashcards Preview

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Flashcards in Chap 6 Standard Errors Deck (11):
1

Central Limit Theorem

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

2

Degrees of Freedom

Roughly the minimum amount of data needed to calculate a statistic. More practically, it is a number or numbers, used to approximate the number of observations in the data set for the purpose of determining statistical significance.

3

Expected Value of the Mean

The value of the mean one would expect to get from a random sample selected from a population with a known mean.
i.e. if one knows the population has a mean of 5 on some variable, one would expect a random sample selected from the population will also have a mean of 5.

4

Inferential Statistics

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

5

Sampling Distribution of the Differences b/w the Means

The distribution of scores that would be generated if one were repeatedly draw two random samples of a given size from a 2 populations and calculate the difference b/w the sample means

6

Sampling Distribution of the Mean

The distribution of scores that would be generated if one were to repeatedly draw random samples of a given size from two population and calculate the mean for each sample drawn.

7

Sampling Distribution

A theoretical distribution of any statistic that one would get by repeatedly drawing random samples of a given size from the population & calculating the statistic of interest for each sample.

8

Standard Error

The standard deviation of a sampling distribution.

9

Statistically Significant

A term indicating that a phenomenon observed in a sample( or samples) has meaningful implications for the population.
i.e. That the difference b/w a sample mean and a population mean is statistically significant or that a relationship observed b/w 2 variables in a sample is strong enough, relative to the standard error, to indicate a relationship b/w the 2 variables in the population from which the sample was selected.

10

sx ̅

The standard error of the mean estimated from the sample standard deviation.
i.e. when a population standard deviation is unknown

11

ox ̅

The standard error of the mean when the population standard deviation is known.