Describing Quantitative Data with Numbers

the average of all the individual data values. To find the mean, add all the values and divide by the total number of data values; given by the formula x bar = sum of data values/number of data values

number that describes some characteristic of a sample

a number that describes some characteristic of a population

a measure is resistant if it isn’t sensitive to extreme values

the midpoint of a distribution, the number such that about half of the observations are smaller and about half are larger; if the n of data values is odd, the median is the middle value in the ordered list, if the number of n data values is even, use the average of the two middle values in the ordered list

the distance between the minimum value and the maximum value; Range = Maximum - Minimum

measures the typical distance of the values in a distribution from the mean; calculated by finding an average of the squared deviations and then taking the squared root

the average squared deviation

divide the ordered data set into four groups having roughly the same number of values

the median of the data values that are to the left of the median in the ordered list

the median of the data values that are to the right of the median in the ordered list

the distance between the first and third quartile of a distribution; IQR = Q3 - Q1

consists of the minimum, the first quartile (Q1), the median, the third quartile (Q3), and the maximum

a visual representation of the five-number summary