Flashcards in Chapter 9- Single Sample T test Deck (18):

1

## What is the t distribution?

### The t distribution allows us to compare two groups

2

## Name the 3 t distributions

### The 3 t distributions are: single sample t test, the paired sample t test, and the independent t test

3

## When does a researcher use the t distribution?

### The researcher uses the t distribution when they wan to compare to samples and the population standard deviation is unknown

4

## Name the 2 distributions and are they observed or theoretical?

### Population (theoretical-M cursive, standard deviation is a small o), Sample Distribution (Observed- X bar, standard deviation is SD), and Sampling (theoretical- double M cursive and regular, standard deviation is standard error)

5

## What is a single sample t test?

### A single sample t-test is when you compare data from one sample to a population where we know the mean but not the standard deviation.

6

## What does the t statistic tell us?

### The t statistic tells us the distance of a sample mean from a population mean in terms of standard error

7

## What correction is made to the t statistic formula when calculating the standard error? What does this correction do?

### Reduce the denominator (N) by subtracting 1. Dividing by a slightly smaller number increases the value of the standard deviation. This is done because there is some level of error when estimating the population SD

8

## After the correction is made, why does a researcher need to make his spread of the distribution of means smaller?

### The spread of the distribution of means needs to be made smaller to reflect the fact that the distribution of means is less variable than a distribution of scores

9

## What is the degrees of freedom?

### The degrees of freedom is the number of scores that are free to vary when estimating a population parameter from a sample

10

## When does the t distribution come close to the z distribution?

### The t distribution becomes close to the z distribution as the sample sizes increase

11

## Name the 6 steps of the Single Sample t test?

### 1) Identify pops, dibs, and assumps 2) State the null/research hypothesis 3) Determine the characteristics of the comparison dibs 4) Determine the critical values or cut offs 5) calculate the test statistic 6) make a decision

12

## What test is run for effect size for the single sample t test?

### For effect size, Cohen's d is run for the single sample t test

13

## What is a paired sample t test?

### A paired sample t test is used to compare two means for a within groups design (every participant is in both samples)

14

## A single sample t test is used to analyze a single sample of scores; a paired sample t test is used to analyze what?

### For the paired sample test, the difference score is analyzed. The paired sample t test is a distribution of mean difference scores

15

## When is a paired samples t test used?

###
A paired samples t test is when researchers have data for all participants under two conditions ( a within groups design)

16

## What is calculated in in a paired samples t test?

### In a paired samples t test, a researcher calculates the difference between two within scores for each person.

17

## The paired sample uses what distribution?

### The paired sample uses the sampling distribution

18