Basic Statistics

is the proportion (or percent) of observations within a category and is found using the formula

Relative frequency= frequency/sum of all frequencies

lists each category of data together with the relative frequency

is constructed by labeling each category of data on either the horizontal or vertical axis and the frequency or relative frequency of the category on the other axis. Rectangles of equal width are drawn for each category. The height of each rectangle represents the category's frequency or relative frequency. 

is a bar graph whose bars are drawn in deccreasing order of frequency or relative frequency. 

is a circle divided into section. Each sector represents a category of data. The area of each sector is proportional to the frequency of the category. 

is constructured by drawing by drawing rectangles for each class of data. The height of each rectangle is the frequency or relative frequency of the class. the width of each rectangle id the same and the rectangles touch each other. 

the smallest value within the class

the largest calue within the class

the difference between consecutive lower class limits 

if first class has no lower class limit or the last class has no upper class limits. 

class width= largest data value -smallest data value/ number of classes

frequency of each value of the variable is evenly spread out across the values of the variable

highest frequency occurs in the middle and frequencies tail off to the left and right of middle.

tail to right of peak is longer than the tail to the left of the peak

tail to left of peak is longer than the tail to the right of the peak.

when value of variable is measured at different points in tie

obtained by plotting the time in which a variable is measured on the horizontal axis and the corresponding value of the variable on the vertical axis. Line segments are then drawn connecting the points. 

constructed by drawing rectangles for each class of data. The height of each rectangle is the frequency or relative frequency of the class. The width of each rectangle is the same and the rectangles touch each other. 

categories into which data are grouped

smallest value witin the class

largest value within the class

1. Decide number of classes. Should be between 5-20 classes. Smaller the data set, fewer classes you should have

2. Compute class width

          Largest data value- smallest Data Value/ # of classes.

         Round value up to convenient number

Step1: Stem of a data value will consist of the digits to the left of the right most digit. The leaf of a data value will be the rightmost digit

Step 2: Write the stems in a vertical column in increasing order. Draw a vertical line to the right of the stems

Step 3: Write each leaf corresponding to the stems to the rigt of the vertcal line

Step 4: Within each stems, rearrange the leaves in ascending order, title the plot, and include a legend to indicate what the values represent.