Home 
Miscellaneous

WGU RFC 1 ch 12
Embed Code  If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
WGU RFC 1 ch 12
Summary of Chapter 12
Question  Answer 

Formulas for statistical procedures are  just basic mathematical procedures 
first step toward analysis  involves converting behavioral responses into some numeric system or categorical organization 
Frequency  refers to the number of times something occurs; with descriptive statistics 
Nominal or ordinal variables  frequency count by each value is very descriptive 
frequency  is more complicated for interval or ratio variables 
Measures of central tendency  indices that represent a typical score among a group of scores 
mean  arithmetic average of the scores, most frequently used measure of central tendency; appropriate for describing interval or ratio data 
median  midpoint in a distribution; 50% of the scores are above the median, and 50% are below the median; most useful when looking at ordinal variables or data sets in which the scores vary widely over distribution 
mode  score that is attained by more subjects than any other score (i.e., occurs most frequently); a set of course may have two or more modes; when nominal data are collected, the mode is the only appropriate measure of central tendency 
two sets of data that are very different can have identical means or medians  creating a need for measures of variability, indices that indicate how spread out a group of scores are 
the range  simply the difference between the highest and lowest score in a distribution and is determined by subtraction 
quartile deviation  one half of the difference between the upper quartile (75th percentile) and the lower quartile (25 percentile) in a distribution 
quartile deviation  more stable measure of variability than the rand and is appropriate whenever the median is appropriate 
variance  defined as the amount spread among scores, if the variance is small the scores are close together, if it is large, the scores are more spread out 
standard deviation  square root of the variance of a set of scores; it is the most stable measure of variability and takes into account every score 
when plotted as a frequency graph a normal distribution forms a bell shape  normal curve 
when distribution is not normal  it is said to be skewed, there are more extreme scores at one end than the other 
negatively skewed  the extreme scores are at the lower end of the distribution 
positively skewed  the extreme scores are at the upper or higher end of the distribution 
percentile rank  indicates the percentage of scores that fall at or below a given score 
percentiles  are appropriate for data measured on an ordinal scale 
standard score  reflects how many standard deviations a students score is above or below the mean 
T score  z score transformed to eliminate pluses or minuses 
measures of relationship  indicate the degree to which two sets of scores are related 
degree of relationship  expressed as a correlation coefficient, which is computed from two sets of scores from a single group of participants 
Pearson r  most appropriate measure of correlation when the sets of data to be correlated are expressed as either interval or ratio scales 
Pearson r  not valid if the relation between variables is not linear 
Spearman rho  appropriate measure of correlation when the variables are expressed as ranks 
Created by:
Xyrarose