Section 3.2 3-Frequency DistributionsEx: The data below represent observations made on the stress scores (on ascale of 0 (low) to 150 (high)) of 140 individuals prior to a stress reductionclass. 1Section 3.2 3-Frequency DistributionsIt is helpful to take an unorganized data set and convert to a data array—an ordered set of data.2Section 3.2 3-Frequency DistributionsA frequency distribution or frequency table for a numerical data set (population or sample) consists of groups of possible values for the variable involved, called classes, and the number of measurements or observations in each class, called frequencies. Often, each frequency is converted to a proportion or percentage of the total number of observations, called a class relative frequency.Class Class Mid-point10-<20 10-19 1520-<30 20-29 2530-<40 30-39 3540-<50 40-49 4550-<60 50-59 5560-<70 60-69 6570-<80 70-79 7580-<90 80-89 8590-<100 90-99 95100-<110 100-109 105 3Section 3.2 3-Frequency Distributions Class Class Mid-pointFreq RelFreqCum Freq10-<20 10-19 15 1 .007 120-<30 20-29 25 8 .057 930-<40 30-39 35 14 .100 2340-<50 40-49 45 19 .136 4250-<60 50-59 55 27 .193 6960-<70 60-69 65 21 .150 9070-<80 70-79 75 22 .157 11280-<90 80-89 85 15 .107 12790-<100 90-99 95 11 .079 138100-<110 100-109 105 2 .014 140Read pp. 49-55, STR 3.2
View Full Document
Unlocking...