– Who spend more time on the daily commute, Sydney-siders or Melbournians?– Statement you regular encounter in the media: such as “Men earn more money than women”; or “Smoking shortens smokers’ lives by about 12 years”11Sample characteristics vs. population characteristics•Sample characteristics – what you calculate from the sample, e.g., average satisfaction for HP computer among male respondents is 1.51•Population characteristics–The “true” values (e.g., “true” satisfaction for HP computer among male customers–What your RQs are about–Unfortunately, the values are unknown (and unknowable in this case)•In its essence, the hypothesis testing process is to use observable relationships between sample characteristics to make inference about relationships between the unknown population characteristics12
MKF21215Variability•Sample characteristics are random variables, e.g., if you collect data for a few times—e.g., with different samples, or at different times—you will get different sample averages•This variability is an issue that needs to be accounted for with statistical analysis (in another word, is the difference in satisfaction we observe in the sample between men and women real, or just noise?)•The first step is to quantity the variability in sample characteristics in your data (e.g., through metrics such as variance and standard deviation)13How do you really “answer” a research question? The ritualistic dance of hypothesis testing1. Problem Definition2. Clearly State the Null and Alternative Hypotheses3. Choose the relevant statistical test4. Calculate p-value5. Is p-value<0.05?NoDo not reject nullReject null hypothesisYes141. Problem definition4/6/201715You have done this already, i.e., your research question•Do men and women differ in their satisfaction with HP computer?