Ch 17 Descriptive Univariate Statics Flashcards
A description of the number or percentage of times the various attributes of a variable are observed in a sample.
frequency distributions
The most frequently observed value or attribute.
mode
The sum of the values of several observations divided by the number of observations.
mean
The value of the “middle” case in a rank ordered set of observations.
median
An ambiguous term that generally suggests “typical” or “normal.” Mean, median, and mode are specific examples of mathematical averages.
average
The distribution of values around some central value, such as an average.
dispersion
A descriptive statistic that portrays how far away from the mean individual scores on average are located.
standard deviation
A level of measurement that describes variables (such as gender or ethnicity) whose different attributes are categorical only, and can be described in terms of how many but not degree.
nominal level of measurement
Head counts of how many cases there are in nominal categories.
frequencies
A level of measurement describing variables whose attributes may be rank-ordered according to degree. An example would be socioeconomic status as composed of the attributes high, medium, and low
ordinal level of measurement
A level of measurement that describes variables (such as IQ or Fahrenheit temperature) whose attributes are rank-ordered and have equal distances between adjacent attributes, but which do not have a true zero point.
interval level of measurement
A level of measurement that describes variables (such as age or number of children) whose attributes have all the qualities of interval measures and also are based on a true zero point
ratio level of measurement
A term for various statistics that portray the strength of association between variables. Effect-size statistics might refer to the degree of correlation between variables (that is, between zero and plus or minus one) or to the difference between the means of two groups divided by the standard deviation.
effect size
An effect size statistic that shows how much more or less likely a certain dependent variable outcome is for the categories of the independent variable.
odds ratio
An effect size statistic that divides the proportion of unsuccessful outcomes in one group by the risk of unsuccessful outcomes in the other group.
risk ratio
An effect size statistic that divides the difference between the experimental group mean and the control group mean by the pooled standard deviation of the two groups.
Cohen’s d
The importance, or meaningfulness, of a finding from a practical standpoint.
substantive significance (practical significance)
The substantive significance or meaningfulness of a finding in a study of the effectiveness of a clinical intervention.
clinical significance
Statistical computations that describe either the characteristics of a sample or the relationship among variables in a sample. Descriptive statistics merely summarize a set of sample observations, whereas inferential statistics move beyond the description of specific observations to make inferences about the larger population from which the sample observations were drawn.
descriptive statistics
The body of statistical computations that is relevant to making inferences from findings based on sample observations to some larger population.
inferential statistics
A general term that refers to the likelihood that relationships observed in a sample could be attributed to chance (sampling error) alone.
statistical significance
A statistical procedure for calculating the probability that a relationship can be attributed to chance (sampling error).
test of statistical significance
