APSY 2-20 - Pop. 2)-Example o Null vs. Research Null: Men...

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APSY 2/20/08 Hypothesis Testing - Hypothesis stated prior to research (Research Hypothesis) o People who own pets have lower blood pressure than those who don’t. - Null Hypothesis o Pets have no effect on blood pressure. o Consider the probability that the result of a study could have come about if the experimental procedure had no effect o If probability is low, then the null hypothesis can be rejected, supporting research hypothesis. - Research population o Those people who receive the experimental treatment or are potentially different form the comparison population. - Comparison population o A control population that didn’t get the experimental treatment or sometimes the population at large. - Null vs. Research hypothesis o Null: No difference between population (HO: Pop. 1 = Pop. 2) o Research: Prediction about difference between population (H1: Pop. 1 >
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Unformatted text preview: Pop. 2)-Example o Null vs. Research Null: Men and women do not differ in IQ scores (Pop 1 = Pop 2) Research: Men and women do differ (Pop 1 ≠ Pop 2) If null is not rejected, research is inconclusive-Null Hypothesis Testing (NHST) steps o State both hypothesis o Using mean, and SD of comparison population, determine your sample’s Z score on the comparison distribution. o Decide whether to reject the null hypothesis based on the traditional cut off level of 0.05. o If null is true, chances are that sample mean will fall between your critical values. (See picture on slide) o Using a cut off level (alpha) of .05 (5%) where 95% in normal distribution is between +/- 1.96 standard scores. o Called the 5% level of significance o...
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This note was uploaded on 04/08/2008 for the course APSY 210 taught by Professor Pipitone during the Spring '08 term at SUNY Albany.

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