Download presentation
Presentation is loading. Please wait.
Published byBlanche Parsons Modified over 9 years ago
1
A.P. Psychology Statistics Notes
2
Correlation The way 2 factors vary together and how well one predicts the other Positive Correlation- direct relationship where factors increase or decrease together Negative Correlation – Inverse relationship where one factor goes up while one goes down
4
Continued… Illusory Correlation -perceiving correlation when none exists -we notice random coincidences as not random, rather as correlated
5
Statistical Reasoning Mode – the most frequently occurring score in a distribution Mean – the arithmetic average of a distribution Median – the middle score in a distribution
7
Measures of Variation Range – the difference between the highest and lowest scores in a distribution Standard Deviation – A computed measure of how much scores vary around the mean score Statistical Significance – A statistical statement of how likely it is that an obtained result occurred by chance
8
68-95-99.7 Rule In practice, one often assumes that the data are from an approximately normally distributed population.normally distributed If that assumption is justified, then about: – 68% of the values are within 1 standard deviation of the mean –about 95% of the values are within two standard deviations –and about 99.7% lie within 3 standard deviations.
9
68-95-99.7 Rule
10
Skew A distribution is skewed if one of its tails is longer than the other. –Positive Skew - long tail in the positive direction. –Negative Skew - long tail in the negative direction. –No Skew – symmetric, normal distribution. Distributions with positive skew are sometimes called "skewed to the right" whereas distributions with negative skew are called "skewed to the left."
11
Positive Skew
12
Negative Skew
13
No Skew (Normal Distribution)
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.