Chapter 5 collecting and organizing data Flashcards
Descriptive statistics
Provide a summary of the main features of a set of data collected from a sample of participants.
Frequency distribution
A table that records the number of times each score in a set of scores occurs.
histogram
graph of frequency distribution in bar form
inferential statistics
Used to draw conclusions about the broader population on the basis of a study using a sample of that population.
Interquartile range
he range of scores lying between the bottom 25 percent of a set of scores (25th percentile) and the top 25 percent of scores (75th percentile); yields a measure of variability unaffected by outliers.
Mean
The arithmetic average of a dataset, found by adding the scores and dividing by the total number of scores in the set.
Median
The middle score of a dataset; an equal number of scores is both above and below the median.
median location
the place in the sequence of scores where the median lies
mode
the most frequentley appearing score in the data set
normal curve
A theoretical frequency distribution for a population; a bell-shaped curve.
outliers
In a dataset, a data point so deviant from the remaining points that the researcher believes it cannot reflect reasonable behaviour and its inclusion will distort the results; often considered a score more than three standard deviations from the mean.
population
all members in a identifiable group
range
in a score set, the difference between the biggest and smallest value
sample
a portion or subset of the population
standard deviation
A measure of deviation of a set of scores from the mean score; the square root of the variance.
variance
A measure of the average squared deviation of a set of scores from the mean score; the standard deviation squared.
