SCM ch. 3 Flashcards
categorical data
data that are described as a category or label.
index point
marks the middle of the data values and is used to determine the position of the median in the data set.
left skewed distribution
the shape of the distribution when the median is higher than the mean
mean
a measure that is calculated by adding up all the values in a data set and then dividing the result by the number of observations
measures of central tendency
measures that use a single value to describe the center point of a data set
median
the value in a data set for which half the observations are higher and half the observations are lower
mode
the value that appears most often in the data set
outliners
values that are much higher or lower than most of the data
right skewed distribution
the shape of a distribution when its mean is higher than its median
weighted mean
allows you to assign more weight to certain values and less weight to others when calculating the mean
measures of variability
measures that determine how much of a spread there is within a data set
range
a measure of variability that is found by subtracting the lowest value from the highest value in a data set
standard deviation
the square root of a distributions variance
variance
a measure that describes the relative distance between the data points in a set around the mean of the data set
chebyshev`s theorm
this states that regardless of whether a distribution is bell shaped, for any number z-score greater than one, at least 94% of the data values will fall within +- four standard deviations of the mean, at least 89% of the data values will fall +- three standard deviations of the mean, and at least 75% of data values will fall +- two standard deviations of the mean.
coefficient of variation
a measure of the standard deviation in terms of its percentage of the mean
empirical rule
this states that if a distribution follows a bell shaped, symmetrical curve centered around the mean, approx 68%, 95%, and 99.7% of the values fall within one, two, and three standard deviations around the mean, respectively.
outliers
extreme values in the data set that require special consideration
z-score
a measure that identifies the number of standard deviations a particular value is from the mean of its distribution
midpoint
the halfway point in a set of data. it can be found by taking the average of the endpoints for each class.
box and whisker plot
a graphical display showing the relative position of a distributions three quartiles as a box on a number line, along with the min and max values
five number summary
a list that consists of a distributions min value, first, second, and third quartiles, and the max value
interquartile range (IRQ)
the difference between the first and third quartiles. it corresponds to the data in the middle 50% of the range.
measures of relative position
measures that compare the position of one value in relation to other values in a data set
percentiles
measure the approx percentage of values in the data set that are below the value of interest
percentile rank
identifies the percentile of a particular value within a set of data
Pth percentile
the approx percentage of values in the data set that are below the value of interest (where p is any number between 1 and 100)
quartiles
the first, second, and third quartiles are 25th, 50th (median), and 75th percentiles, respectively.
