Class Notes (839,313)
Canada (511,260)
Psychology (3,335)
PSYC 305 (53)
Lecture 4

Lecture 4 - Jan 18.doc

2 Pages
43 Views

Department
Psychology
Course Code
PSYC 305
Professor
Heungsun Hwang

This preview shows 80% of the first page. Sign up to view the full 2 pages of the document.
Description
PSYC305 Lecture 4 - Jan. 18 Limitations of z-test: • Knowing the true value of the standard deviation of a population is unrealistic Alternative? - t-test • • Where standard deviation of population is unknown Hypothesis Testing About a Single Mean: t-test: • Purpose: • To test whether a sample mean significantly differs from a population mean • Prior Requirements/Assumptions: • The population is normally distributed • The mean of the population must me known • The sample must be a simple random sample of the population Thus, t statistic is obtained by replacing the standard deviation of the population mean with the • sample counterpart in z statistic • Due to this replacement, t statistic does not follow the standard normal distribution anymore. In- stead, it follows the t-distribution • The t-distribution was discovered by William S. Gosset in 1908. Gosset was a statistician employed by the Guinness brewing company which had stipulated that he not publish under his own name. He therefore wrote under the pen name ‘Student’. • Also called Student’s t distribution The t Distribution: • Varies in shape according to the degrees of freedom (DF) = N-1 • The t distribution approaches the standard normal distribution as DF becomes large • The approximation is quite good for DF > 30 Hypothesis Testing About a Single Mean: t-test: • Calculate the value of t-statistic (or simply t-value) for your sample mean with µ and M M Look into how extreme your t-value is • • Look at the table of t values and find the critical
More Less
Unlock Document

Only 80% of the first page are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit