9.12 EBDM Basic Statistics Flashcards
Measure that pertains to the population, almost always unobservable. Characteristic of a population. Describes the entire population
parameter
Characteristic of a sample (measure based on a sample). We can use this to estimate a population parameter.
statistic
if there is a skew and the peak is to the right and the tail is to the left, it is a _____ skew
left
if there is a skew and the peak is to the left and the tail is to the right, it is a _____ skew
right
mean, median, and mode are measures of _______
location
range, inter-quartile range, variance, standard deviation are measures of ________
dispersion
how far the values are away from the mean. A larger _____ means more uncertainty
variance
square root of variance is _____
SD
repeated measurements give the same/similar results. is this reliability or validity?
reliability
when a tool measures what it is supposed to, the “truth” it is ______.
valid
concept of validity
what is Intra-rater reliability
measure once by one person, measure again by same person and it is around the same
what is inter-rater reliability?
measure once by one person, measure again by another person - same/similar results
temporal reproducibility:
measure today, measure tomorrow, same/similar results
do reliable results mean the data is valid?
no
does a measure have to be reliable to be valid?
yes
there are two TYPES of measurement: what are they?
categorical and continuous
there are four LEVELS of measurement, what are they?
nominal, ordinal, interval, ratio
a nominal level of measurement is ________ (categorical or continuous?). What does it measure?
categorical
measures categories that have no order (occupation, gender, eye color, blood type)
an ordinal level of measurement is _______ (categorical or continuous?). What does it measure?
categorical
measures categories that have an order/direction (pain - poor, excellent, OK…. size small, medium, large)
an interval level of measurement is _______ (categorical or continuous?) what does it measure?
either categorical or continuous
data on a scale with an arbitrary 0 point and quantitative differences between two measurements (temperature, etc)
in interval levels of measurement, is a ratio meaningful? is a range?
a ratio is NOT meaningful and a range is.
a ratio level of measurement is _________ (categorical or continuous?) what does it measure?
either categorical or continuous.
measures something with a true/absolute zero point where ratio between two is meaningful (blood pressure, weight, cholesterol)
what level of measurement would you use for something that you think of as “twice as much, three times as much”
ratio level of measurement
on a scatterplot, you can see _______ between two variables
correlation
the LINEAR relationship between two variables on a scatterplot is called what?
the correlation coefficient
what are the two extremes of the correlation coefficient for a scatterplot?
-1 to 1
if there is no significant correlation coefficient for a scatterplot does that mean there is no correlation?
NO, it could be a non-linear correlation
___________ is the technique to study if a dependent variable changes with an independent variable
regression
linear regression analysis can _______ dependent variable using the independent variable
predict
in ____________ analysis, one postulates the statistical model that two variables, X and Y are related by a straight line
linear regression
the best fitting line between the points assuming two variables are linearly related
regression line
