A characteristic or measure obtained by using the data values from a sample
Statistic
A characteristic or measure obtained by using all the data values from a specific population
Parameter
ymbol for population mean
M
symbol for sample mean
_
x
The median is ______________ the mean by extrememly high or extrememly low values.
affected less than
The mean is affected by _______.
extremely high or low values, called outliers, and may not be the appropriate average to use in these situations.
n a positively skewed or right-skewed distribution the "tail" is _____
O.
to the right
In a negatively skewed or left-skewed distribution the "tail" is _____
to the left
Data values are evenly distributed on both sides of the mean; the distribution is unimodal; the mean, median and mode are the same and are at the center of the distribution
Symmetric Distribution
he symbol for population standard deviation
O
the symbol for sample standard deviation
s
he symbol for sample variance
s2
he symbol for population variance
o2
When the standard deviation is large,
he more variable the data are.
Coefficient of Variation is ________________________ .
used to compare standard deviation when the units are different
Chebyshev theorem _____________ require a specific distribution.
does not
Empirical Rule _______ require a bell-shaped/symmetric distribution
bell-shaped
A student with a percentile rank of 81 would mean that the student ____________ of the students.
did better than 81%
A z-score represents __________
the number of standard deviation that a data value falls above or below the mean
An outlier is _____________ .
an extremely high or extremely low data value when compared with the rest of the data values.
A two-column chart listing the categories
and frequencies
Frequency Distributions
frequency/total
Total relative frequency=1
Relative frequency
A bar chart with the bars organized from most to least
Pareto Chart
A circle segmented based on relative frequencies as percentages.
pie chart
The set of numbers we are determining the frequency
class
smallest & largest numbers that can be included in a class
class limits
: the range of numbers that can be in a class
class width
: are used to make sure we do not overlap the class limits
class boundaries
the middle of the class
class midpoint
(largest data value - smallest value)/# classes*
*Round UP
Class width =
single value for the class
Ungrouped
range of values for the class
grouped
The sum of the frequencies up to and including that class
Cumulative frequency
describe the sample/population
desriptive statisctics
inferance about the sample or population
inferential statistics
a characteristic or attribute that can assume different variables
variable
occur by chance
random variable
are the values the variables can be
data
each individual value
data value/datum
is all the data
data set
ex: zip code
qualitative
gender, height, weight
quantitative
countable
discrete
often measurements usually a range
continuous
variables that are assoiciated with what we are trying to measure and influence our outcome
confounding variables
samples in which each subject did not have the same chance of being selected
bias sample
the 1st subject is selected than every 5th subject after that
systemic sampling
subjects are split into groups or strata and from each group are selected at random
stratified sampling
the population can naturally be classified into groups or clusters
cluster smapling
the group we leave alone
control group
the group the treatment is given
experimental group
the variable that explains our response
independent variable
the vraiable that measures the response
dependent variable
the treatment applies is unknown
blinding
subject patient only doesnt know the treatment
single blinding
subject/patient and doctor doesnt know the treatment
double blinding
the sample may not be representative of the population
suspect samples
the word average takes on different meansings (mean, median, mode)
ambiguious averages
the results can be reported in such a way that makes it appear horrific
changing the subject
the statistics may not be compared to anything and is therefore detached
detached statistics
often times studies people imply a product may benefit you in one way or another
implied connections