Descriptive Statistics: Reliability &
Validity
descriptive statistics - correct answer ✔✔statistics used to organize and describe
data
measures of central tendency - correct answer ✔✔statistical methods for observing
how data cluster around the mean
normal distribution - correct answer ✔✔a symmetrical distribution with a single
numerical representation for mean, median, and mode
standard deviation - correct answer ✔✔represents the typical amount that a score is
expected to vary from the mean in a set of data.
percentile ranks - correct answer ✔✔scores that express the percentage of students
who scored as well as or lower than a given student's score
z-score - correct answer ✔✔derived scores that are expressed in standard deviation
units, with a mean of 0 and a standard deviation of 1
stanines - correct answer ✔✔a method of reporting scores that divide data into 9
groups and scores are reported as 1 through 9 with a mean of 5.
deciles - correct answer ✔✔scores that are reported in 10 groups ranging from a
score of 10 for the lowest grouping to 100 for the highest group of scores, with each
group representing 10% of the obtained scores
raw scores - correct answer ✔✔the first scores obtained in testing; usually
represents the number of items correct
