Descriptive Statistics > How to Draw a Frequency Distribution Table

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## How to Draw a Frequency Distribution Table: Overview

A

**frequency distribution table**is one way you can organize data so that it makes more sense. For example, let’s say you have a list of IQ scores for a gifted classroom in a particular elementary school. The

**IQ scores**are: 118, 123, 124, 125, 127, 128, 129, 130, 130, 133, 136, 138, 141, 142, 149, 150, 154. That list doesn’t tell you much about anything. You could draw a

**frequency distribution table**, which will give a better picture of your data than a simple list.

## How to Draw a Frequency Distribution Table: Steps.

**Step 1:** Figure out how many classes (categories) you need. There are no hard rules about how many classes to pick, but there are a couple of general guidelines:

- Pick between 5 and 20 classes. For the list of IQs above, we picked 5 classes.
- Make sure you have a few items in each category. For example, if you have 20 items, choose 5 classes (4 items per category), not 20 classes (which would give you only 1 item per category).

Note: There is a more mathematical way to choose classes. The formula is log(observations)\ log(2). You would round up the answer to the next integer. For example, log17\log2 = 4.1 will be rounded up to become 5. (Thank you to Ayman Masry for that tip).

**Step 2:** Subtract the minimum data value from the maximum data value. For example, our IQ list above had a minimum value of 118 and a maximum value of 154, so:

154 – 118 = **36**

**Step 3:** Divide your answer in Step 2 by the number of classes you chose in Step 1.

36 / 5 = **7.2**

**Step 4:** Round the number from Step 3 up to a whole number to get the class width. Rounded up, 7.2 becomes **8**.

**Step 5:** Write down your lowest value for your first minimum data value:

The lowest value is **118**

**Step 6:** Add the class width from Step 4 to Step 5 to get the next lower class limit:

118 + 8 = **126**

**Step 7:** Repeat Step 6 for the other minimum data values (in other words, keep on adding your class width to your minimum data values) until you have created the number of classes you chose in Step 1. We chose 5 classes, so our 5 minimum data values are:

118

126 (118 + 8)

134 (126 + 8)

142 (134 + 8)

150 (142 + 8)

**Step 8:** Write down the upper class limits. These are the highest values that can be in the category, so in most cases you can subtract 1 from the class width and add that to the minimum data value. For example:

118 + (8 – 1) = 125

118 – 125

126 – 133

134 – 141

142 – 149

150 – 157

**Step 9:** Add a second column for the number of items in each class, and label the columns with appropriate headings:

IQ | Number |
---|---|

118-125 | |

126-133 | |

134-141 | |

142-149 | |

150-157 |

**Step 10:** Count the number of items in each class, and put the total in the second column. The list of IQ scores are: 118, 123, 124, 125, 127, 128, 129, 130, 130, 133, 136, 138, 141, 142, 149, 150, 154.

IQ | Number |
---|---|

118-125 | 4 |

126-133 | 6 |

134-141 | 3 |

142-149 | 2 |

150-157 | 2 |

That’s How to Draw a Frequency Distribution Table, the easy way!

Like the explanation? Check out our statistics how-to book, with hundreds more step by step solutions, just like this one!

**Tip**: If you are working with large numbers (like hundreds or thousands), round Step 4 up to a large whole number that’s easy to make into classes, like 100, 1000, or 10,000. Likewise with very small numbers — you may want to round to 0.1, 0.001 or a similar division.

If you prefer an online interactive environment to learn R and statistics, this *free R Tutorial by Datacamp* is a great way to get started. If you're are somewhat comfortable with R and are interested in going deeper into Statistics, try *this Statistics with R track*.

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I was so confused but this article helped me alot

Do you choose any number between 5-20 for frequency f or the is a formula for it,um stuck pls help

Choose a number that works for your data. The goal is to show a nice, clear graph of your output. How many data points do you have?

Nice one….it realy helpd me in my exams

It’s really easy .but didn’t understand the step8 and further.

But by watching the video I understand.

God bless u.

Hi, Aneela,

Is it the “upper class limits” that you’re stuck on?

Stephanie

Wonderful Thanks for this info

so clear and helpful. i just can’t even bother people around me anymore. thank u alot…

Thanks for explanation Allah bless you