Business Stats Chapter 3

can be used to summarize the location, variability, and shape of data distribution

when numerical values are obtained are for a sample

numerical values obtained for a population

mean, median, mode, weighted mean, geometric mean, percentiles, and quartiles

range, interquartile range, variance, standard deviation, coefficient of variation

Skewness

data distribution skewed to the left

data distribution is skewed to the right

covariance and correlation coefficient

graphical summary of data based on a five-number summary

theorem that can be used to make statements about the proportion of data values that must be within a specified number of standard deviations of the mean

A measure of relative variability computed by dividing the standard deviation by the mean and multiplying by 100.

measure of linear association between two variables that takes on values between -1 and +1

Values near +1 indicated strong positive linear relationship
Values near -1 indicate a strong negative linear relationship; Values near 0 indicate the lack of a linear relationship

a measure of linear association between two variables.
Positive values = positive relationship
Negative values = negative relationship

a rule that can be used to compute the percentage of data values that must be within on, two, and three standard deviations of the mean for data that exhibit a bell-shaped distribution

a technique that uses five numbers to summarize the data
min, Q1, median, Q3, max

a measure of location that is calculated by finding the nth root of the product of n values

a measure of variability, defined to be the difference between the third and first quartiles

a measure of central location by summing the data values and dividing by the number of observations

a measure of central location provided by the value in the middle when the data are arranged in ascending order

measure of location, defined as the value that occurs with greatest frequency

unusually small or unusually large data value

a value such that at leas p percent of the observations are less than or equal to this value and at least (100 - p) percent of the observations are greater than or equal to this value
50th percentile = median

A sample statistic, such as, x-bar, s^2, and s, used to estimate the corresponding population parameter.

numerical value used as a summary measure for a population (population mean, u, population variance, o^2

The 25th, 50th, and 75th percentiles, referred to as the first quartile, the second quartile (median), and third quartile, respectively. The quartiles can be used to divide a data set into four parts, with each part containing approximately 25% of the data.

measure of variability
largest value -- smallest value

A numerical value used as a summary measure for a sample

A measure of the shape of a data distribution.

Data skewed to the left result in negative skewness; a symmetric data distribution results in zero skewness; and data skewed to the right result in positive skewness.

measure of variability computed by taking the positive sqrt of the variance