Flashcards in Round 2 Lecture 3 Deck (17)

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1

## A Parameter

### is a summary measure computed to describe a characteristic of the population

2

## A Statistic

### is a summary measure computed to describe a characteristic of the sample

3

##
A Hypothesis

### is a claim about a population parameter

4

##
Null Hypothesis (H0)

###
Opposite of the alternative hypothesis

May or may not be rejected based on empirical evidence

5

## Alternative Hypothesis (Ha)

### Generally the hypothesis that the researcher claims

6

## two-sided alternative

### we are equally interested in deviations on either side of the null hypothesis value.

7

## one-sided alternative

### An alternative hypothesis that focuses on deviations from the null hypothesis value in only one direction

8

##
Logic of Hypothesis Test

###
-We start by assuming that the null hypothesis is true

-Then we look at the data and check if there is enough evidence to reject the null hypothesis.

-This is the logic of jury trials. In court, the null hypothesis is that the defendant is innocent.

-The evidence takes the form of facts that seem to contradict the presumption of innocence.

9

## P-value

### is the probability of seeing the observed data (or something even less likely) given the null hypothesis.

10

## statistically significant

### We can define a “rare event” arbitrarily by setting a threshold for our P-value. If our P-value falls below that point, we’ll reject the null hypothesis

11

## The threshold is called

### an alpha level

12

## The alpha level is also called

### the significance level

13

## False positive

###
The null hypothesis is true, but we mistakenly reject it.

type 1 error

14

## False Negative

###
The null hypothesis is false, but we fail to reject it.

type 2 error

15

##
Hypothesis about dependence between two discrete (categorical) variables:

### Use Chi-square test

16

##
Hypothesis about means of two different groups (i.e., relationship between a continuous variable and a discrete variable with two categories):

### Use t-test

17