MA 3110 STATS CHAPTER 3 Flashcards
(19 cards)
Measure of center
A value at the center or middle of a data set
Arithmetic mean or mean
A set of data is the measure of center found by adding the data values and dividing the total by the number of data vales.
The median of a data set
The measure of center that is the middle value when the original data values are arrayed in order of increasing (or decreasing) magnitude. Is often denoted by x~ (pronounced “x-tilde”.
Mode of a data set
The value that occurs with the greatest frequency.
Midrange of a data set
The measure of center that is the value midway between the maximum and minimum values in the original data set. It is found by adding the max data value to the min data value the dividing the sum by 2
Midrange of a data set FORMULA
MAX DATA VALUE + MIN DATA VALUE /2= MIDRANGE
Skewed
Data that is not symmetric and extends more to one side than to the other.
Skewed left (data negatively skewed)
Data to the left have a longer left tail, and the mean and median are to the left of the mode.
Skewed right (data positively skewed)
Data skewed to the right have a longer right tails, and the mean and median are to the right of the mode.
Range of a set of data values
The difference between the maximum data value and the minimum data value.
Range FORMULA
Range=max data value - min data value
Standard deviation of sample values
Denoted by “s” is a measure of variation of values about the mean.
Variance of a set of values
A measure of variation equal to the square of the standard deviation.
CV Coefficient of variation
A set of nonnegative sample or population data, expressed as a percent, describes the standard deviation relative to the mean.
Standardized value or ‘z’ score
The number of standard deviations that a given value “x” is above or below the mean.
Percentiles
Measures of location, which divide a set of data into 100 groups with about 1% of the values in each group.
Quartiles
Measures of location, denoted Q1, Q2, and Q3, which divide a set of data into four groups with about 25% of the values in each group.
5-number summary
A set of data that consists of the minimum value, the first quartile Q1. The median (second quartile) Q2, the third quartile Q3, and the maximum value.
Boxplot (or box-and-whicker diagram)
A graph of a data set that consist of a line extending from the minimum value to the maximum value, and a box with lines drawn at the first quartile Q1, the median, and the third quartile Q3.
