# PSY201H1 Chapter Notes - Chapter 3: Percentile Rank, Cumulative Frequency Analysis, Frequency Distribution

## Document Summary

How scores are to be presented when there are many so that we can see the shape of the distribution. To construct a frequency distribution of grouped scores. Determine the width of each class interval (i) Remember to count each unit, so 50-55 isn"t 5 units wide, it"s 6 units wide. List the limits of each class interval, placing the interval containing the lowest score value at the bottom. Start with the lowest, which must contain the lower limit of the interval. Make the lower limit divisible by i! So if the lowest unit is 42, start with 40 if the i is 5 or 10. Tally the raw scores into the appropriate class intervals. Add the tallies of each interval to obtain the interval frequency. Relative frequency, cumulative frequency, and cumulative percentage distributions. Indicates the proportion of the total number of scores that occurs in each interval. Relative frequency = f/n [frequency divided by total number of scores]