Descriptive stats for psych

Descriptive Statistics for Psychology

Hours Studied Tally Frequency Total Hours Studied10 I 1 109 III 3 278 IIII 4 327 IIII 5 356 IIII III 8 485 IIII II 7 354 IIII 5 203 IIII 4 122 II 2 41 I 1 10 0 N=40 ∑ = 224 Total hours studied = Hours studied X frequency

The mean, the arithmetic average of allscores under consideration, is computedby dividing the sum of the scores by thenumber of scores. 224 = 5.6 = mean number of hours studied for the exam 40

The median is the point at which 50% ofthe observations fall below and 50% aboveor, in other words, the middle number of a 10set of numbers arranged in ascending or 9descending order. 8 7 6 5 4 3 2 1 0

The mode is the number that appears most often Hours Studied Frequency 10 1 What is the Mode 9 3 according to this table? 8 4 7 5 6 8 5 7 4 5 3 4 2 2 1 1 0 0

Histogram

negative positive

Now it’s your turn!Descriptive Statistics ActivityBelow is a random sample of grades from a recent quiz.90, 60, 65, 70, 85, 95, 50, 80, 70, 60, 50, 65, 75, 80, 85, 70, 65, 55, 100, 65, 70, 85,80, 65, 751. Calculate the Mean, median, and mode. a. Create a histogram. b. Is the data normal, negatively, or positively skewed?

Tally Score Frequency totalI 100 1 100I 95 1 95I 90 1 90III 85 3 255III 80 3 240II 75 2 150IIII 70 4 280IIIII 65 5 325II 60 2 120I 55 1 55II 50 2 100

MEDIAN? MODE? 100 100 95 95 90 90 85 85 85 85 85 85 80 80 80 80 80 80 75 75 75 75 70 70 70 <- 70 70 70 70 70 65 65 65 65 65 65 65 65 65 65 60 60 60 60 55 55 50 50 50 50

Descriptive stats for psych

by John Martin on Feb 09, 2012

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