lesson 5 stat

mean

the most commonly used measure of central tendency. It is found by adding the values of the data and dividing by the total number of values

grouped mean

the midpoints of the classes are used for the values of the x.

weighted mean

used when different values in a dataset contribute unequally to the average. Each value is multiplied by a weight, then the products are summed and divided by the total of the weights.

geometric mean

used when averaging ratios, percentages, or growth rates, the geometric mean is the nth root of the product of n values

grand mean

mean of multiple groups of data combined into one dataset. Calculated by combining the means and sizes of groups.

median

midpoint of data array. Before finding this value, the data must be arranged in order, from least to greatest or vice versa. The median will either be a specific value or will fall between two value

grouped median class

in a grouped frequency distribution, the median class is the class interval where the median lies.

Ungrouped quartiles

divide data into 4 equal parts

Ungrouped decile

deciles divide the ordered dataset into 10 equal parts.

Percentile rank

tells the percentage scores below a particular value in the dataset

Mode

The third measure of average is the ___.

• It is the value that occurs most often in the data set.

• A data can have more than one or none at all.

• The only measure of central tendency that can be used in finding the most typical case when the data are nominal or categorical.

Moral class

is the class with the largest frequency.