Flashcards in Chapter 14: Correlated Groups t-Test Deck (11):

1

## When do we use single sample t-test?

###
- mean of null hypothesis population is unknown

- usually only have the mean

2

## What are the limitations of single sample designs?(2)

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- Usually mu is not known

- if u were known, cannot be certain if conditions under which mu was calculated are applicable.

3

## Characteristics of correlated groups designs?(2)

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- Each subject used before conditions ( before and after) aka control and experimental .

- Pairs of subjects matched on one or more characteristic serve in both conditions.

4

## What is the information tested by correlated group design?(2)

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- Difference scores:

* magnitude of difference scores

* direction of difference scores

5

## What are difference scores?

### - random sample from a population of difference scores having a mean of zero!

6

## What is the formula for tobt for correlated groups?

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* Dobt- uD/ Sd/>/N

or Dobt - uD/ >/ SSd/ N(N-1)

7

## What is the formula for SSd for correlated groups?

### - SSd= ED^2 - (ED)^2/N

8

## List the steps to solving a correlated group question!

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1. calculate differences from the before and after values, calculate D^2

2. Calculate the summation of D, summation of D^2

3. Calculate the Dobt= ED/N

4.Calculate SSd than Tobt

5. find df ( N-1)

6. evaluate the statistic based on its sampling distribution. ( look at alpha and use df, look at table D for tcrit )

7. Conclude

9

## Whats the conclusion for evaluation of the statistic?

### - If | tobt | > | tcrit |, reject ho

10

## What is the calculation for Cohen's D? (effect size)

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- d= | Dobt |/ Sd

- Sd= standard deviation sample difference scores

- Dobt= value of mean of the sample difference scores

- d ? estimated d

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