Descriptive Statistics

data presented in ascending or descending order with the frequency of each individual score

ungrouped

data presented in a range of scores with the frequency of scores that fell within a range

grouped

frequency of occurrence of scores up to and including any given value in the data set

cumulative

what type of distribution occurs when the mean, median, and mode are equal

normal distribution

distribution of scores is asymmetrical

skewed distribution

value that occurs most often

mode

midpoint of the data

median

average

mean

how do you calculate range

highest score minus lowest score

how do you calculate standard deviation

square root of the variance

what is the most common and useful measure of dispersion

standard deviation

shows the strength of relationship between two variables

r value

what is the range for r value

-1 to 1

what does an r value close to 1 indicate

strong relationship

what does an r value close to 0 indicate

weak relationship

direct relationship between two variables

positive correlation

inverse relationship between two variables

negative correlation

represents the probability that the findings of the study are due to chance

p value

what is the standard of acceptability for p value

< or = to 0.05

what does it mean if the p value is >0.05

not statistically significant

the degree to which a data collection instrument measures the variable it is designed to measure

validity

refers to the accuracy of a study’s results

internal validity

accuracy of generalizing the results from the sample to the population

external validity

the extent to which the method of measurement performs consistently

reliability

consistent performance by the same investigator when using a data collection instrument

intra-examiner reliability

consistent performance by different investigators when using the same data collection instrument

inter-examiner reliability