Research and Stats (Two) Flashcards
statistics
the field that gives tools to collect and analyze data
sample
a group of people selected, usually randomly, from a larger population of people
statistics
the branch of math that is concerned with the collection and interpretation of data from samples
descriptive statistics
a way of organizing numbers and summarizing them so that they can be understood
two main types of descriptive stats
measures of central tendency
measures of variability
measures of central tendency
used to summarize the data and give one score that seems typical of sample
measures of variability
used to indicate how spread out the data are
frequency distribution
table or graph that shows how often different numbers or scores appear in a particular set of scores
histogram
a common graph, bar graph
polygon
a line graph
normal curve
common frequency distribution
unimodal, symmetric, bell curve
skewed
when distribution isn’t even on both sides of a central score with the highest frequency
skewed distribution
positively or negatively skewed
negatively skewed
concentration in high end (skewed left)
positively skewed
concentration in low end (skewed right)
bimodal distributions
two modes, two high points
measure of central tendency
number that best represents the central part of a frequency distribution
mean, median, mode
mean
arithmetic average of a distribution of numbers
good when normal/low standard deviation
not resistant so not good with outliers
outlier
values that are extreme and therefore distort accuracy
median
score that falls in the middle of an ordered distribution
half of scores above, half below
resistant
mode
most common value
simplest measure
bimodal
has two modes
skewed distributions what happens to mean median mode
mean pulled in direction of tail, mode highest point, median in middle of two
if bimodal what use
none do much good