How to solve a question about probability frequency distribution

Probability 6 Comments

Stuck on a problem in statistics about probability frequency distribution? This how to article will show you how to solve these probability problems in just a few easy steps.

Sample question: In a sample of 43 students, 15 had brown hair, 10 had black hair, 16 had blond hair, and 2 had red hair. Use a frequency distribution table to find the probability a person has neither red nor blond hair.

Step 1: Make a table.
List the items in one column and the tally in a second column.
probability frequency distribution

Step 2:Add up the totals.
In the sample question we’re asked for the odds a person will not have blond or red hair. In other words, we want to know the probability of a person having black or brown hair.

Brown = 15/43 (15 out of 43 students have brown hair)
Black = 10/43 (10 out of 43 students have black hair)

15/43 + 10/43 = 25/43 (25 out of 43 students have either brown or black hair)

You’re done!

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6 Responses to “How to solve a question about probability frequency distribution”

  1. How to Do Everything Statistics » How to find the probability of a simple event happening said:

    Aug 23, 09 at 8:42 am

    [...] articles on this topic: Finding the probability of an event not happening Finding probabilities using frequency distributions Probability of getting certain cards from a [...]

  2. Jennifer Thomas said:

    Oct 25, 09 at 8:36 pm

    This was helfpul and simplified things for me.

  3. How to Do Everything Statistics » How to find the probability of an event NOT happening said:

    Dec 15, 09 at 9:41 am

    [...] Probability questions are often word problems that appear more difficult than they actually are. The trick is to identify the type of probability problem you have. This article will tell you how to find the probability of a simple event not happening. (You might also be interested in: Finding the probability of an event occurring, or How to  find the probability of an event not happening using frequency distributions). [...]

  4. Thomas said:

    Apr 18, 12 at 7:25 am

    How do you solve this problem:
    52% of business travelers plan their trips less than two weeks before departure. The study is replicated in the tri-state area with a sample of 122 frwquent business travelers. Develop a probabilty distribution for the number of travelers who plan their trip within two weeks of departure.

    Thanks

  5. Andale said:

    Apr 18, 12 at 10:25 am

    Hi, Thomas,

    Can you post this question on the forum? One of our moderators will be happy to answer stats questions :)

    Thanks for dropping by!

  6. How to Find Probability | said:

    Apr 21, 13 at 6:52 am

    [...] Do you have a frequency distribution to work with? Or are you able to construct a frequency distribution table with your given data? For example, you have x number of items with a certain traits. This article deals with finding probabilities using frequency distribution tables. [...]