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

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## 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.).

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## Confidence Interval

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

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## 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.

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## 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.

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## 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)

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## 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)

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## 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.

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## Practical Significance

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

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## 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.

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## Random Sampling Error

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

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## Sample

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

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## 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.

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## 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).

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## Type 1 Error

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

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## p value

### The p value, or the probability

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## ∝

### The alpha level 0.5

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## d

### One measure of effect size

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## S

### Standard deviation used in the effect size formula

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## ∞

### Infinity

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## sx ̅

### The standard error calculated with the sample standard deviation

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## ox ̅

### The standard error calculated with the population standard deviation

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## Ho

### The null hypothesis

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## HA or H1

### The alternative hypothesis

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## Point Estimate

### Point estimate provides a single plausible value for a parameter

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## Confidence Interval

###
A plausible range of values for the population parameter

Note: confidence intervals only attempt to capture population parameters.

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## 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

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

### z* x SE

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## Type 2 Error

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

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