11-21-08 - Psychology 206 Class Notes TYPE I ERROR Test...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Psychology 206 – Class Notes – 11/21/08 TYPE I ERROR Test statistic z exceeds the critical value and we reject H0 But, H0 is (in reality) TRUE This is type I Error Researcher directly controls probability of Type I error with critical values Probability of Type I error is called alpha (alpha = .05 most common; alpha = .01, alpha= .001) We say: “The probability of Type I error is alpha=.05” Exercise #27 The null hypothesis is that the mean of the population of (birth) weights of infants born to mothers who smoke is greater than or equal to 2.81 kg. The mean of population of (birth) weights of infants born to mothers who smoke is significantly less than 2.81 kg. The null hypothesis is ALWAYS OPPOSITE OF THE ALTERNATIVE HYPOTHESIS. To be sure that your null hypothesis is correct, formulate your alternative hypothesis before you make your null hypothesis. LOOK FOR THE KEY TO EXERCISE #27- Monday Just make sure that you have enough room for your distributions, shade your rejection regions, check your null hypotheses, check your inequalities TYPE II ERROR Type II error is when you fail to reject the null hypothesis when it is really wrong Test statistic “Z” does NOT exceed the critical value, so we
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/03/2009 for the course PSYCH 206 taught by Professor Kenney-benson during the Fall '07 term at Allegheny.

Page1 / 3

11-21-08 - Psychology 206 Class Notes TYPE I ERROR Test...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online