I. Measures of Variability (Video Lesson 5 I) (YouTube version)
II. The Range
Range = high score � low score III. Average Mean Deviation
IV. The Relationship Between Population/Sample and Variance/Standard Deviation (Video Lesson 5 IV) (YouTube version)
V. Variance
VI. Standard Deviation (Video Lesson 5 VI) (YouTube version)
Additional Videos on the Concepts that might help: Range, Variance, Standard Deviation How to Calculate Standard Deviation and Variance What is Variance in Statistics? Finding the Standard Deviation of a Data Set Standard Deviation Why is computational formula better than definitional formula?The computational formula does not require the mean value, and it computes the SS by using the X values only. Hence, the computational formula would be easy to use when only the X values are provided.
What is the difference between definitional and computational formula?the formal verbal definition of a statistical concept. For example, the definitional formula of variance states that it is the mean squared difference between a score and the mean of all of the scores. This contrasts with the computational formula, which is the equation used to calculate values for the concept.
Why some researchers may prefer to use the computational formula as opposed to the definitional formula?The definitional formula is easy to use when the mean is a whole number and there are relatively few scores. b. The computational formula is preferred when the mean is not a whole number.
In which circumstances is the computational formula preferred over the definitional formula when computing ss the sum of the squared deviations for a population?The computational formula is better when the mean is a fraction or decimal value and usually easier with a large number of scores.
|