lecture3

# lecture3 - Frequency Distributions(Chapter 2 Types of...

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± Frequency Distributions (Chapter 2) ± Types of frequency distributions ± Making frequency tables and graphs ± Percentiles, percentile ranks, and interpolation Statistics Characterize attributes of Sample and/or population Make generalizations about Population base on sample Descriptive Inferential ± Most basic characterization of the entire sample ± Types ± Simple, relative, and cumulative

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± First step ± get some data ± Change detection ± Dependent variable: time to detect change ± Data (seconds x 10 to detect change) ± 5, 4, 6, 7, 8, 9, 1, 3, 4, 1, 7, 5 ± What do we know? ± Sample size ± n=12 ± List in order: 1, 1, 3, 4, 4, 5, 5, 6, 7, 7, 8, 9 ± min = 1 ± max = 9 Time (x) # responses (f) 91 81 72 61 52 42 31 20 12 Total # of Scores: ± f = n = 12
± Each score is expressed as a proportion of the total n Xfp% 91 . 0 8 3 8 . 3 81 . 0 8 3 8 . 3 72 . 1 6 7 1 6 . 7 61 . 0 8 3 8 . 3 52 . 1 6 7 1 6 . 7 42 . 1 6 7 1 6 . 7 31 . 0 8 3 8 . 3 20 0 . 0 0 12 . 1 6 7 1 6 . 7 ± f = n = 12 p = f/n % = p*100 ± p = 1.0 ± % = 100 CHECKS!! ± Shows total, f, p, or % at each value and all lower ranked values ± Begin at the bottom of the table and move upwards ± Useful for determining the relative standing of scores ± Cumulative percents are called percentile ranks ± % of observations with the same or smaller value Xfp%c f c % . 0 8 3 8 . 3 1 2 1 0 0 . 0 8 3 8 . 3 1 1 9 1 . 7 . 1 6 7 1 6 . 7 1 0 8 3 . 3 . 0 8 3 8 . 38 6 6 . 7 . 1 6 7 1 6 . 7 7 5 8 . 3 . 1 6 7 1 6 . 7 5 4 1 . 7 . 0 8 3 8 .

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## This note was uploaded on 02/18/2011 for the course PSYCH 5 taught by Professor Collins during the Fall '08 term at UCSB.

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lecture3 - Frequency Distributions(Chapter 2 Types of...

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