Exam 1 Flashcards
A set of observations drawn from the population of interest
A sample
Includes all possible observations about which we would like to know
a population
Why are samples most often used
researchers are rarely able to study every person in a populations
obersvations of physical, attitudinal, and behavioural characteristics that can take on different values
Variables
what is a variable
any observation of a characteristic that can take on different values
____ observations can only take on specific values (whole numbers)
Discrete
_____ observationos can take on a full range of values
continuous
is a nominal variable discrete or continuous?
discrete
is an ordinal variable discrete or continuous?
discrete
___ variables are used for observations that have categories or names as their values. they are qualitative, not quantitative
nominal
____ variables are used for observations that have rankings as their values (i.e. 1st, 2nd, 3rd)
ordinal
what are the two types of variables that are discrete?
ordinal and nominal
what are the two types of variables that are continuous?
interval and ratio
_____ variables are used for observations with a numerical value and a relative, arbitrary zero
interval variables
what kind of variable is temperature?
interval
____ variables are variables that have numerical values, but zero is meaningful
ratio
which type of observations exist on a scale?
conintuous observation
a scale variable is another term for a _____ variable that meets criteria to be either interval or ratio
continuous
_____ are the discrete values or conditions that variables can take on
levels
what is a predictor variable
has at least two levels that can either be manipulated or observed to determine its effects on the outcome variable
another word for independent variable
what is an outcome variable
another word for dependent variable
the variable that is hypothesised to be related to or caused by changes in the predictor variable
what is a confounding variable
any variable that impacts the predictor variable so that you cannot logically determine which variable is causing the change
the variable that you are measuring is called the
dependent variable
the variable that is the established conditions is called the
independent variable
which variable is the variable you change
independent variable
which variaable is the variable impacted by the change
dependent variable
a ____ measure is consistent
reliable
a ____ measure measures what it is intended to measure
valid
can a measure be valid but not reliable?
no
can a measure be reliable but not valid?
yes
what does a measure need to do in order to be valid
measure what it is supposed to with consistency
drawing conclusions based on whether data supports the hypothesis
hypothesis testing
what is an operational definition
the specific operations and procedures used to measure or manipulate a variable
an association between two or more variables
correlation
a type of predictor variable in which the researcher manipulates the levels of that variable
independent variable
a type of outcome variable in which the researcher measures the response to the manipulation of the IV
dependent variable
a study in which participants are randomly assigned to a condition or level of one or more independent variabled
experiment
with _____ _______, every participant in the study has equal chance of being assignedd to any group or experiemental condition
random assignment
what is a between groups research design?
participants only experience one level of the IV. only measured once
what is a within groups research design
participants in the study experience the different levels of the IV. measured more than once
what is replication
the duplication of scientific results, ideally in a different context or with a sample that has different characteristics
what is it called when researchers outline their research design and analysis plan before conducting a stuy
preregistration
data in its original state before anything is done to is is called
raw scores
describes the pattern of a set of numbers by displaying a count or proportion for each possible value of a variable
frequency distribution
a visual depiction of data that shows how often each value occurred
frequency table
what is an outlier
an extreme score that is either very high or very low in comparison to the rest of the scores in a sample
allows researchers to depict data visually by reporting frequencies within a given interval, rather than the frequencies for a specific value
grouped frequency table
when is a grouped frequency table helpful
when you have a lot of data that would make a normal frquency table hard to analyse
what is a histogram
looks like a bar graph but only depicts one variable and its frequencies
a frequency distribution that is bell shaped, symetric, and unimodal
normal distribution
distributions in which one of the tails is pulled away from the center
skewed distributionos
when a distribution is positively skewed the tail is pulled to the _____
right
when a distribution is negatively skewed, the tail is pulled to the ____
left
situation that prevents variables from taking on a value below a certain point
floor effect
is floor effect part of a positive or negative skewer
positive
is ceiling effect part of positivev or negative skew
negative
what is the ceiling effect
variables prevented from taking on a value above a certain point
graph that displays each data point in a sample with the range of scores along the x axis and a dot for each data point above the appropriate value
dot plot
a graph that depicts the relation between two continuous variables
scatterplot
when are scatterplots commonly used
in correlational research
in a _____ graph, every line can reveal a relationship due to how it curves or breaks
scatterplot
a ______ ______ between two variables means that the relationship is best described by a straight line
linear relation
a _____ _____ between two variables means that the relationship is best described by a line that breaks or curves in some way
nonlinear relation
used to illustrate the relation between two continuous variables
line graphs
what is a time plot (or time series plot)
a graph that plots a continuous variable on the y axis as it changes over an increment of time (labelled on the x axis)
a visual depiction of data in which the IV is nominal or ordinal, and the DV is continuous. the height represents the average value of the DV for each category
bar graph
a type of bar graph in which the categories along the x axis are ordered from highest bar to lowest bar
pareto chart
what is a pie chart
graph in the shape of a circle, with a slice for every level of the IV. size of slice represents proportion of each level/category
if therer is one continuous variable with frequencies, which type of graph should you use
a histogram
if there is one continuous IV and one continuous DV, what two types of graphs can you use
scatterplot or line graph
if there is one nominal or ordinal IV and one continuous DV what type of graph should you use
bar graph
if there are two or more nominal or ordinal IV and one continuous DV what type of graph should you use
bar graph
what is chartjunk
unnneccesary info or feature in a graph that detracts from ability to understand data
what is a moire vibration
any visual pattern that creates a distracting impression of vibration or movement
a background pattern like graph paper that data is presented on and makes bars confusing
grid
features of data that has been dressed up to be something other than just data
ducks
______ _____ allows us to visualise every point in the dta set while displaying summary statistics
strip plots
the descriptivev stat that best represents the center of a data set
central tendency
how is the mean calculated
adding all values and dividing by how many values there are
numbers basedd on samples taken from a population are called
statistics
numbers based on whole populations are called
parameters
what is the median
the middle when scores arrnged in order
how is the median calculated
values ordered, find middle score
for even number of values find the average of the middle two scores
what is the mode
scrore the appears most frequently in a data set
how is mode calculateded
counting how many times a score appears and taking the most common one
when a distribution of scores has one mode it is called
unimodal
when a distribution of scores as two modes is is called
bimodal
when a distributiono of scores has more than two modeas is is called
multimodal
if a distribution of scores is complletely even the mode is called
trick question. there is no mode
a numerical way of describing how much spread there is in a distribution
variability
measure of variability that is calculated by subtracting the lowest score fromm the highest score
range
what is the interquartile range
measure of the distance between the first and third quartiles
what is a box plot
a graph that depicts overal distribution of a data set. lower end marks first quartile, upper end marks third quartile
the average of the squared deviations from the mean
variance
when is mode used
- when one score really dominates
- distribution is bimodal or multimodal
- data is nominal
the amount that a score in a sample differs from the mean of the sample
deviation from the mean
how to calculate variance
- subtract mean from evevry score
- square every deviationo
- sum all squared deviations
- divide sum of squares by total number in the sample
the square root of the average if the squared deviations from the mean
standard deviation
how to find standard deviation
unsquare the variance -> take the square root
