ec41lecture14_handout

# ec41lecture14_handout - Statistics for Economists Lecture...

This preview shows pages 1–9. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Statistics for Economists Lecture 14 Kata Bognar UCLA t-Interval Procedures Hypothesis Testing Statistics for Economists Lecture 14 Kata Bognar UCLA May 20, 2010 Statistics for Economists Lecture 14 Kata Bognar UCLA t-Interval Procedures Hypothesis Testing Announcements • Midterm solutions are online • Homework 5 solutions will be uploaded later this afternoon Statistics for Economists Lecture 14 Kata Bognar UCLA t-Interval Procedures Hypothesis Testing Last Lectures • Sampling distributions • Point and interval estimators Statistics for Economists Lecture 14 Kata Bognar UCLA t-Interval Procedures Hypothesis Testing Today’s Outline 1 t-Interval procedure 2 Hypothesis testing 3 Readings: Weiss, Chapter 8.4, 9.1 - 9.2 4 Readings for next class: Weiss, Chapter 9.3 - 9.6 Statistics for Economists Lecture 14 Kata Bognar UCLA t-Interval Procedures Hypothesis Testing Known Population Standard Deviation • The sampling distribution of the sample mean is the basis for finding confidence intervals for the population mean. • The sampling distribution of the sample mean, ¯ X is • normal with μ ¯ x = μ and σ ¯ x = σ √ n whenever the population is normal. • approximately normal with μ ¯ x = μ and σ ¯ x = σ √ n whenever the sample is large ( n > 30). • Thus, when the population σ is known, the distribution of the random variable Z = ¯ X- μ σ/ √ n is • standard normal whenever the population is normal. • approximately standard normal whenever the sample is large ( n > 30). Statistics for Economists Lecture 14 Kata Bognar UCLA t-Interval Procedures Hypothesis Testing Unknown Population Standard Deviation • What to do if we do not know the population standard deviation? • We estimate the population standard deviation by the sample standard deviation, s . • The random variable T = ¯ X- μ s / √ n follows a Student’s t-distribution with a degree of freedom n- 1. Statistics for Economists Lecture 14 Kata Bognar UCLA t-Interval Procedures Hypothesis Testing t-Distribution Statistics for Economists Lecture 14 Kata Bognar UCLA t-Interval Procedures Hypothesis Testing Properties of the t-Distribution • The total area under a t-curve is 1....
View Full Document

{[ snackBarMessage ]}

### Page1 / 18

ec41lecture14_handout - Statistics for Economists Lecture...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online