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
measures of variability
used to discover how spread out the scores are from each other
range
difference between highest and lowest score
not resistant so not good to use when there are outliers
standard deviation
square root of average deviation of scores from mean
smaller is better
empirical rule
68 in 1, 95 in 2, 99.7 in 3
z score
how many standard deviations you are away from the mean
(x - mean)/standard deviation
inferential statistics
allows researchers to draw conclusions or make inferences about results of research and about whether results are only true for specific group involved in study or whether results can be applied to or generalized to the larger population
tells how much confidence should have in relationship
statistically significant
a way to test differences to see how likely those differences are to be real and not just caused by the random variations in behavior that exist everywhere
t test
a formula that results in a single number t that evaluates the probability that the difference between the two group means is due to pure chance or luck
probability symbolized by letter p
p meanings
if p > 0.05 then not valid
if p less than or equal to 0.05 then can draw conclusions from data
significant difference
a difference thought not to be due to chance
tests
t test (determines if two means are different from each other) f test or analysis of variance chi square
f test or analysis of variance
determines if three or more means are different from each other
can evaluate more than one independent variable at a time
chi square
compares frequencies of proportions between groups to see if they are different
basic research
research to collect data not to solve problem
applied research
research trying to solve problem, psychology is mainly applied research
ethnocentrism
belief that groups you’re part of are better/more favorable
