Class notes
PSYCH 107 Ch 10 notes
- Course
- Institution
This is a comprehensive and detailed note on Chapter 10; the t test 2 independent samples for psych 107. *Essential Study Material!! *For you, at a price that's fair enough!!
[Show more]
Seller
Follow
anyiamgeorge19
Reviews received
Content preview
Ch 10: The T Test for 2 Independent SamplesIndependent-Measures Designs
the research designs that are used to obtain the 2 sets of data can be
classified in 2 general categories:
o the 2 sets of data could come from 2 completely separate groups of
participants
o the 2 sets of data could come from the same group of participants
the first research strategy, using completely separate groups, is called:
o an independent-measures or a between-subject
The Null Hypothesis and the Independent-Measures t Statistic
the goal of an independent-measures research study is to evaluate the mean
difference between 2 populations (or between 2 treatment conditions)
o using subscripts to differentiate the two populations, the mean for the
first population is μ1, and the second population mean is μ2
o the difference between means is simply μ1 – μ2
o as always, the null hypothesis states that there is no change, no effect,
or no difference
the null hypothesis for the independent-measures test:
o H0 : μ1 – μ2 = 0 (no difference between the population means; μ1 = μ2)
the alternative hypothesis states that there is a mean difference between the
2 populations:
o H1 : μ1 – μ2 ≠ 0 (there is a mean difference)
o the alternative hypothesis can simply state that the 2 population
means are not equal
μ 1 ≠ μ2
Independent-Measures Notations
1
, The Formulas for an Independent-Measures Hypothesis Test
the independent-measures t uses the difference between 2 sample means to
evaluate a hypothesis about the difference between 2 population means
o thus, the independent-measures t formula is:
in each of the t-score formulas, the standard error in the denominator
measures how accurately the sample statistic represents the population
parameter
o in the single-sample t formula, the standard error measures the
amount of error expected for a sample mean and is represented by SM
for the independent-measures t formula, the standard error measures the
amount of error that is expected when you use a sample mean difference (M1
– M2) to represent a population mean difference (μ1 – μ2)
o the standard error for the sample mean difference is represented by
the symbol S(M1 – M2)
Calculating the Estimated Standard Error
to develop the formula for S(M1 – M2) we consider 3 points:
o each of the 2-sample means represents its own population mean, but
in each case there is some error
o the amount of error associated with each sample mean is measured by
the estimated standard error of M
o for the independent-measures t statistic, we want to know the total
amount of error involved in using 2 sample means to approximate 2
population means
to do this, if the samples are the same size, we will find the error
from each sample separately and then add the 2 errors together
when the samples are of different sizes, a pooled, or average,
estimate (that allows the bigger sample to carry more weight in
determining the final value) is used
Hypothesis Tests and Effect Size with the Independent-Measures t Statistic
2
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller anyiamgeorge19. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for CA$14.42. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
79202 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now