1 / 11

REVIEW OF BASICS PART II

REVIEW OF BASICS PART II. Probability Distributions Confidence Intervals Statistical Significance. Probability Distributions. Probabilities are relative frequencies Probabilities vary between 0 and 1. z - SCORES. z-score: standard score measuring in units of standard deviations

isadora-cooley
Télécharger la présentation

REVIEW OF BASICS PART II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. REVIEW OF BASICS PART II • Probability Distributions • Confidence Intervals • Statistical Significance

  2. Probability Distributions • Probabilities are relative frequencies • Probabilities vary between 0 and 1

  3. z - SCORES • z-score: standard score measuring in units of standard deviations • standard normal distribution: normal distribution in z-score units

  4. Confidence Intervals • Range of values thought to contain the population mean • Go up and down from the sample mean • Level of confidence determines how many standard deviations to go

  5. 99% 95% 68% MEAN -3SD -2SD -1SD +1SD +2SD +3SD

  6. STATISTICAL SIGNIFICANCE • Inferential statistics are used to make inferences about populations based on samples • These inferences are based on hypothetical probability distributions

  7. Sampling Distribution • Hypothetical frequency distribution of all the sample means from a population • Sampling variation • Standard error: standard deviation of sampling distribution

  8. Testing the Null • Null Hypothesis: no difference • Assume the Null Hypothesis is true until proven other wise • Reasonable doubt standard (p < .05) • Reject or Fail to Reject the Null

  9. Confusion about p • p is the probability of a Type I error: rejecting the Ho when the Ho is true • What is the probability that you could get results this extreme if the Ho is true? • NOT the probability that the Ho is true given these results

  10. Problems with NHST • Binary decision • Does not show effect size • Null is probably never literally true

  11. Take-Home Points • We can make probabilistic statements about a population • It’s better than guessing

More Related