Statistics S1
bimodal
2 peaks
negative
Standard dev. can never be ____
five number summary, because it includes the IQR
When interpreting skewed data, it is best to use ________ to describe it
density curve
a curve with an area beneath it of exactly 1 that describes the overall pattern of a distribution
observational study
a sample survey is a type of ____
sample
a subject of the population
placebo
a treatment w/o any affect or active ingredient
lurking variable
a variable that has an important effect on the relationship among variables in a study but isn't one of the explanatory variables being studied
population
al individuals in which we are interested in
association
as x increases, does y increase or decrease? --> used for nonlinear data
common response
both explanatory and response variable are responding to some lurking variable
mean, median, min, max
changes when you add/subtract data
mean median, min, max, standard dev, range, IQR (everything)
changes when you multiply or divide data
observational study
collecting data w/o interfering in any way
comparative observational study
compare 2 or more groups to determine effect differences
normal curve
describes a distribution that's symmetric, unimodal, bell shaped
correlation
direction, strength, form, shows relationship between varaibles
standard dev, range, IQR
doesn't change when you add or subtract data
extrapolation
estimating a value that lies outside of the data set
interpolation
estimating a value that lies within the data set
standardized value (z-score)
explains how far from the mean a certain score is in units of standard deviation
explanatory variable
explains or causes changes in the response variable, x value
sampling variability
if you take different surveys, there are going to be slightly varying results
in the direction of the skew
in a skewed distribution, the mean moves ....
subject
individuals in an experiment
least-squares regression line
line that makes the sum of the squares of vertical distance data points from the line as small as possible
range
max-min
central tendencies
mean, median, "middle", peaks, modes
standard deviation
measure of spread using actual data values
quantitative variable
measurements w numbers and units , makes sense to do math
response variable
measures on outcome or result of a study, y value
five-number summary
minimum, Q1, med, Q3, max
r
number that describes correlation, decimal number between -1 and 1
median and IQR
of the following measures: median, mean, IQR, and standard deviation, which are not affected by outliers
unimodal
one peak
mean and standard deviation
parameters that describe density curves
categorical variable
responses that group individuals into a category
distribution of a variable
says what value the variable takes and how often it takes these values, can be displayed w a bar graph or pie chart
gaps
separations between groups or points
scatter plot
shows relationship between 2 sets of data w/ 2 variables graphed as ordered pairs on a coordinate plane
regression analysis
stat process for estimating the relationship between variables
sample survey
study a sample
experiment
study in which we apply a "treatment" or otherwise affect the results
census
study of the entire population
variable
the characteristic of the individuals that the data describe
residual
the difference between an observed value and a value predicted
isn't
the mean ______ resistant to extreme values
is
the median _____ resistant to extreme values
counts
the number of times each response occurs
individuals
the people, animals, objects, etc. that the data describe
rates
the percent or proportion of all responses it represents
1. ask a question 2. produce data 3. analyze data 4. interpret results
the statistical problem-solving process
outlier
value that's much higher/lower than the rest of the data
pie chart and bar graph
what are two good ways to measure categorical data
response
what happens to the subjects in response to the treatment
treatment
whatever is done y the experiment that's different
bivariate data
when you measure 2 variables at the same time
