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Class 17

Class 17. Review of Hypothesis Tests and Scales of Measurement The special case of success/fail outcomes. Use Pivot Table to create. Use Pivot Table to create. Create from data in the question. You calculate this. Excel Data Analysis. T-test: Two-sample for means, equal variances .

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Class 17

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  1. Class 17 Review of Hypothesis Tests and Scales of MeasurementThe special case of success/fail outcomes

  2. Use Pivot Table to create Use Pivot Table to create Create from data in the question You calculate this. Excel Data Analysis

  3. T-test: Two-sample for means, equal variances. Pivot table Data analysis

  4. T-test: Two-sample for means, equal variances. Pivot table Data analysis Or…the question may give you the summary stats.

  5. T-test: Two-sample for means, equal variances. Pivot table Data analysis Or…the question may give you the summary stats. BEWARE!It switches tails based on sign of t. Negative because it does F-M

  6. T-test: Paired 2 sample for means(book calls it matched samples) • If the data are paired, use the paired test. • The paired test is EQUIVALENT to a one-sample test of the mean of the differences. • Weights before and after treatment. 72 patients • BA rookie and sophomore years. • Sample mean was lower sophomore year, in part, due to REGRESSION TO THE MEAN. • Extreme outcomes are followed (on average) by less extreme outcomes.

  7. ANOVA: single factor. Pivot table Data analysis

  8. ANOVA: Single Factor • Inference about the equality of several means. • If 3 or more groups, no choice but to use ANOVA • I’ll give you the raw data • Either in two columns (like for Height and IT) • Or in 3 or more columns (one for each group/sample)

  9. The Alternative Hypothesis • Chi-squared goodness of fit • P’s not all equal • Chi-squared independence test • Not independent • T-test of μ=100 • μ≠100, μ>100, μ<100 you decide! • T-test: Two Sample (H0: μM=μF or μM-μF=0) • μM ≠ μF, μM > μF, μM < μF you decide! • ANOVA single factor • Means not all equal H0 is not true

  10. With One-tail alternative • Ha: μM > μF • If sample mean for females was HIGHER than males, then DO NOT REJECT. No need to calculate anything or use DATA ANALYSIS • Excel Data Analysis t-test: two samples will always give you the 1T p-value that is the lower! • If sample mean for females was higher, it assumes that was your alternative….and gives you a misleading p-value.

  11. The special case of Success/Fail Outcomes It’s a categorical variable. It’s a numerical variable. It’s…..special. It’s where we started our course.

  12. Categorical Numerical Roulette IQ 904 spins 34 IQs s=19.8 n=33 Chi-squared GOF

  13. Categorical Success/Fail Numerical Roulette Wunderdog IQ 904 spins 149 Success/fail 34 IQs 149 1’s and 0’s 0.58 n=149 s=19.8 n=33 Chi-squared GOF Chi-squared GOF Binomial

  14. Categorical Success/Fail Numerical Roulette Wunderdog IQ 904 spins 149 Success/fail 34 IQs 149 1’s and 0’s 0.58 n=149 s=19.8 n=33 Chi-squared GOF Chi-squared GOF Binomial

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