Stats Ch 3
most extreme observations that still lie within the lower and upper limits
adjacent values
at least 89% of the observation lie within 3 standard deviations to either side of the mean
chebycher's rule
____ is a resistant measure and is preferred when median is the measure of center
interquartile range
The ____ is typically pulled away from the visual center toward the direction of skewness by unusually large (or unusually small) values
mean
the most commonly used measure of central tendency is ____
mean
these measures of central tendency ____ and ____ apply only to quantitative data
mean median
what are the measures of central tendency
mean median mode
Descriptive measures that indicate where the center, or most "typical value," of a data set lies are called _______
measures of central tendency
____ of a data set is the number that divides the bottom 50% of data from the top 50% of the data
median
The _______ are resistant measures of center because they are not sensitive to a few outliers
median and mode
five number summary includes
min Q1 Q2 Q3 max
this measure of central tendency ____ is for qualitative or quantitative data
mode
observations that fall outside the data pattern
outliers
a descriptive measure for a population
parameter
unlike mean and standard deviation _____ are resistant
percentiles
IQR=
Q3-Q1
median equation when data is in increasing order
X(n+1)/2
deciles
10 equal parts
percentiles
100 equal parts
quartiles
4 equal parts
quintiles
5 equal parts
within a bell shaped distribution we can apply empirical rule saying rougly _____ of observations lie within 3 standard deviations to either side of the mean
99.7%
symmetric mean ____ median left skewed mean_____ median right skewed mean ____ median
= < >
lower limit=
Q1-(1.5*IQR)
upper limit=
Q3+(1.5*IQR)
N=
population size
observations that lie below the lower limit or above the upper limit
potential outliers
median of the part of the data that lies at or below the median of the entire data
quartile 1
median of the entire data set
quartile 2
median of the part of data that lies at or above the median of the entire data
quartile 3
n=
sample size
a descriptive measure for a sample
statistic
almost all the observations in any data set lie within three standard deviations to either side of the mean
three standard deviations rule
a _____ can improve the resistance of the mean by removing a percentage of the smallest and largest observations before computing the mean
trimmed mean
The _____ is the number of standard deviations that the value of x is from the mean
z-score
standardized variable
z=x-mu/sigma
A standardized variable always has mean ____ and standard deviation ____
zero one
