Chapter 14: Correlated Groups t-Test Flashcards Preview

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Flashcards in Chapter 14: Correlated Groups t-Test Deck (11)
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1
Q

When do we use single sample t-test?

A
  • mean of null hypothesis population is unknown

- usually only have the mean

2
Q

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

A
  • Usually mu is not known

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

3
Q

Characteristics of correlated groups designs?(2)

A
  • 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
Q

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

A
  • Difference scores:
  • magnitude of difference scores
  • direction of difference scores
5
Q

What are difference scores?

A
  • random sample from a population of difference scores having a mean of zero!
6
Q

What is the formula for tobt for correlated groups?

A
  • Dobt- uD/ Sd/>/N

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

7
Q

What is the formula for SSd for correlated groups?

A
  • SSd= ED^2 - (ED)^2/N
8
Q

List the steps to solving a correlated group question!

A
  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
Q

Whats the conclusion for evaluation of the statistic?

A
  • If | tobt | > | tcrit |, reject ho
10
Q

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

A
  • d= | Dobt |/ Sd
  • Sd= standard deviation sample difference scores
  • Dobt= value of mean of the sample difference scores
  • d ? estimated d
11
Q

How do you solve for Sd?

A

Square root of: SSd/N-1