Frequency Distribution

Question 1

What is the order of things we need to find with a frequency table (7 things)

Answer 1

1) class width
2) lower/upper class limits
3) boundaries
4) frequency (tally)
5) midpoints
6) relative frequency
7) cumulative frequency

Question 2

How to find class width

Answer 2

Compute (largest data value- smallest data value) divided by (desired number of classes)

You must increase the computed value to the next highest whole number

Question 3

How to find lower and upper class limits
(Suppose our lowest data value is 1 and our class width is 12)

Answer 3

We first fine our lowest data value= 1 
We then add the class with to that= 13
We continue from there and it looks like... 
1-
13-
25-
37-
49- 

To find the upper class limit, we fill in the blanks. If group 2 starts with “13” then that means that group 1 must have ended in “12” and so on. It looks like... 
1-12
13-24
25-36
37-48
49- 60 (add 12)

Question 4

How to find boundaries

Answer 4

To find upper class boundary, add 0.5 unit to the upper class limits

To find lower class boundaries, subtract 0.5 unit from the lower class limit

Question 5

How to find frequency

Answer 5

To find the frequency of a table you tally each number into their class

Question 6

How to find midpoints

Answer 6

Midpoints = (lower class limit+ upper class limit) divided by 2

Question 7

What is relative frequency

Answer 7

Relative frequency are the percentages of the data in each class

Question 8

How to find relative frequency

Answer 8

Take the total of frequency (4+7+2+7+4= 24) divided by the number in the frequency

Example
Frequency Relative frequency
4 4/24 or 0.167 or 16.7%
7 7/24 or 0.292 or 29.2%
And so on

Question 9

How to find cumulative frequency

Answer 9

Add frequency values to the one below and continue.. 
example 
Frequency        Cumulative frequency 
4                         (Same as 4 on frequency) 4 
7                          (4+7)= 11 
2                           11+2= 13 
7                            13+7= 20
4                            20+4= 24 

Total (24) should be to same as the sum of frequency

Question 10

What is a histogram

Answer 10

A paragraph that displays the frequency of a given class. We label the X axis with boundaries of a class and the Y axis with its boundaries

Question 11

Name the three steps in making a histogram

Answer 11

1) Make a frequency table (including relative frequency’s) with the design number of classes
2) Place class boundaries on the horizontal axis and frequencies on the vertical axis
3) For each class of the frequency table, draw a bar who’s with extends between corresponding class boundaries. The height of each bar is a corresponding class frequency