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6 Cards in this Set
- Front
- Back
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Construct a frequency distribution
Construct a histogram |
FD = Score (High to Low)/Frequency (# of each score)
HIS = Highest score - Lowest score/Class Interval you want Establish CI for scores in table Frequency on x axis, Interval on y axis |
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Measures of Central Tendency:
1) Mean 2) Median 3) Mode |
*Average of a set of scores (Add all scores and divide by number of scores)
*Middle score (50% fall above score and 50% below score) * Use over mean if you have a skewed set of scores *Score that occurs the most, captures peak of curve |
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Measures of Variability:
1) Range 2) Inter-quartile Range |
* Subtract lowest score from highest score plus one
* Subtract the score that is 1/4 of the way from the bottom from the score that is 3/4 from the bottom and divide by two. Then add and subtract this number to the median |
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Concept of Standard Deviation
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*Measure of variability that describes how scores vary around the mean
*Helps us understand test scores and is important because in all normal curves the percentage of scores between SD units is the same *Important in examining test scores relative to normal curves |
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Normal Bell Curve
How does it relate to the measures of central tendency? |
*A bell shaped curve that represents a symmetrical distribution that human traits tend to fall along
*Mean, median and mode all fall perfectly in the middle *In a skewed distribution, median is a better measure of central tendency because any unusually low or high score does not distort the median like it does the mean |
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How does the normal bell curve relate to skewed curves?
How does the normal bell curve relate to standard deviation? |
*Sometimes a distribution of scores does not fall in a symmetrical shape or a normal curve
Negatively Skewed: Majority of scores fall toward the upper end Positively Skewed: Majority of scores fall toward the lower end *Important because in all normal curves the percentage of scores between units is the same (0-1SD = 34%, 1-2SD = 13.5%, 2-3SD = 2.25%) |
