1 / 11

Chi-Square Test

Chi-Square Test. Section 12.1. Categorical Variables. Based on observations Univariate – single categorical variable Example: Sample 100 people & ask if they agree or disagree with a question. Bivariate – uses two categorical variables

noelle
Download Presentation

Chi-Square Test

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chi-Square Test Section 12.1

  2. Categorical Variables • Based on observations • Univariate – single categorical variable • Example: Sample 100 people & ask if they agree or disagree with a question. • Bivariate – uses two categorical variables • Example: Sample 100 people & ask if they are male/female and what political party they support.

  3. One-Way Frequency Table - univariate Data Vertical One-Way Table Horizontal One-Way Table

  4. Goodness of Fit Test • Used to measure the extent to which the observed counts differ from the expected counts. • K = # categories of a catagorical variable • Df = k – 1 • Test Statistic:

  5. Assumptions • Observed Values are based on random Samples • Sample size is large – each cell count is at least 5.

  6. Hypotheses • Ho: State each proportion’s hypothesized value. • HA: At least 1 of the proportions differ from the hypothesized value.

  7. It uses the Chi-Square Chart • Positively Skewed • Uses d.f. • On calculator!

  8. Is there a preference in type of car? P1=proportion who prefer a SUV P2=proportion who prefer a truck p3=proportion who prefer a sedan P4=proportion who prefer a sports car Assumptions: Random Samples & all cell counts are at least 5. Use a Chi-Square goodness of fit Test P-val = xcdf(2.24,∞, 3)=0.52

  9. A researcher believes that the number of homicides crimes in CA by season is uniformly distributed. To test this claim, you randomly select 1200 homicides from a recent year and record the season when each happened.

  10. Results from a previous survey asking people who go to movies at least once a month are shown in the table below. To determine whether this distribution is still the same, you randomly select 1000 people who go to movies at least once a month and record the age of each. Are the distributions the same?

  11. Homework • Worksheet

More Related