HTHSCI 2S03 Lecture Notes - Lecture 8: Squared Deviations From The Mean, John Tukey, Cotinine

• School: McMaster University
• Department: Health Sciences
• Course: HTHSCI 2S03
• Professor: Mc Gillion Michael

Document Summary

Dv is measured as interval or ratio (or sometimes ordinal) Identify critical t value from tables (using degrees of freedom, significance level) Compare test statistic ( t ) to critical value. Independent t tests: participants are from different populations (independent) Paired t tests: participants are from similar populations (not independent) Common application: same participants before and after (pre/post designs) Independence pertains to the participants & not the observations on them. Self-pairing (before/after) is only one example of pairing (where paired t tests are used). Other cases where paired t-tests are using are pairs of similar individuals e. g. , 2 students of similar ability, 2 patients matched on age & sex etc. Clients recruited for study were those in whom the 1st attempt at ng tube insertion was unsuccessful. A 2nd attempt at ng tube insertion was made after applying the topical local anaesthetic (xylocaine) Pain measured after 1st & 2nd attempts (pain measured using visual analogue scale, score ranging from 0-100mm)