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B AD 6243: Applied Univariate Statistics

B AD 6243: Applied Univariate Statistics. Hypothesis Testing and the T-test Professor Laku Chidambaram Price College of Business University of Oklahoma. Steps in Hypothesis Testing. Determine hypotheses (null & alternative) Select significance level (  level/p level) Choose a sample size

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B AD 6243: Applied Univariate Statistics

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  1. B AD 6243: Applied Univariate Statistics Hypothesis Testing and the T-test Professor Laku Chidambaram Price College of Business University of Oklahoma

  2. Steps in Hypothesis Testing • Determine hypotheses (null & alternative) • Select significance level ( level/p level) • Choose a sample size • Calculate the value of the statistic • Obtain critical value • Compare results BAD 6243: Applied Univariate Statistics

  3. Errors in Hypothesis Testing Sample (“Trial”) Population (“Truth”) BAD 6243: Applied Univariate Statistics

  4. MAXMINCON Principle • Maximize experimental variance • Design, plan and conduct research so that the experimental conditions are as different as possible • Minimize error variance • Reduce error through controlling experimental conditions • Reduce error by increasing reliability of measures • Control extraneous variance • Randomization: Groups can be considered statistically equal in all possible ways • Selection: To eliminate the effect of an extraneous variable on a dependent variable, choose subjects so that they are as homogenous as possible (on that variable) • Addition: To control the effect of an extraneous variable, build it into the research design, so as to measure its effect on the dependent variable BAD 6243: Applied Univariate Statistics

  5. Differences between Groups • Randomized groups • Random sampling; random assignment • Simple vs. factorial designs • Concerns: • (Pre-experimental) equality of groups • Unequal cell sizes • Correlated group(s) • Use same units in different treatments • Single vs. multi-group designs • Concerns: • History, maturation and sensitization BAD 6243: Applied Univariate Statistics

  6. Concepts Related to the T-test • Degrees of freedom • T-distribution vs. standard normal distribution • Level of significance • Between subjects design: • Equal sample sizes • Equal variance • Within subjects design BAD 6243: Applied Univariate Statistics

  7. Standard Normal Distribution BAD 6243: Applied Univariate Statistics

  8. t Distributions t-distributions refer to a family of distributions, which like normal distributions, are bell-shaped, but whose shape changes with the sample size; smaller sample sizes have flatter distributions, while larger sizes approximate normal distributions BAD 6243: Applied Univariate Statistics

  9. Independent Samples t-test BAD 6243: Applied Univariate Statistics

  10. Independent Samples Error Bar BAD 6243: Applied Univariate Statistics

  11. T-test as a Regression Model BAD 6243: Applied Univariate Statistics

  12. Dependent Samples T-test BAD 6243: Applied Univariate Statistics

  13. Dependent Samples Error Bar BAD 6243: Applied Univariate Statistics

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