Lecture13 - 1 Lecture 13 Comparison and control: The...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Lecture 13 Comparison and control: The difference between two proportions 2 Overview You can already calculate and interpret confidence intervals hypothesis tests for a single population proportion e.g., proportion of applicants who get hired Today youll learn the same thing for the difference between two population proportions ( 1 2 ) e.g., difference between proportion 1 of female applicants who get hired proportion 2 of male applicants who get hired Well also reinforce how to use a control group as a comparison 3 Sex discrimination In government: "I'm not for women, frankly, in any job. I don't want any of them around. Thank God we don't have any in the Cabinet." "I don't think a woman should be in any government job whatever. I mean, I really don't. The reason why I do is mainly because they are erratic. And emotional." Richard Nixon, 37 th President of the U.S., 1969-1974 In orchestras: I just dont think women should be in an orchestra. Zubin Mehta conductor, LA Symphony, 1964-1978 conductor, NY Philharmonic, 1978-1980 There is one woman in the Vienna Philharmonic. out of ~100 musicians 4 Difference in population proportions Over the last 50 years, both women (population 1) and men (population 2) have auditioned for symphony orchestras Some proportion of female auditioners has been hired: 1 and some proportion of male auditioners has been hired 2 Let the null hypothesis be absence of discrimination State the hypotheses in formal symbols 1- 2 =0 (no discrimination) 1 1- 2 <0 (discrimination against women) One tail or two? 5 Difference in sample proportions ( adapted from Goldin & Rouse 2000) old audition records of certain major orchestras summarized in a bivariate table basically two parallel frequency tables, one for women, one for men Note : Table cells (white) sum to table margins (black) Questions : How many men were rejected? How many women tried out? How many musicians were hired? How many musicians tried out? Women Men Row totals Rejected 589 1072 1661 Hired 10 30 40 Column totals 599 1102 1701 aka contingency table (contab) aka cross-tabulation 6 Bivariate table: Another view 589/ 599=98.33% 1072/1102=97.28% 1661/1701=97.65% 98.33%+1.67%=100% etc....
View Full Document

Page1 / 30

Lecture13 - 1 Lecture 13 Comparison and control: The...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online