Relative Frequency/ Probability Word problem help!!!

Jul 2016
East Coast
I am drowning in math right now and would love some help bc I am horrible at math.

Here is what I have got.

1. The four major blood groups are designated A, B, AB and O. Within each group there are two types; positive and negative. Find data on the relative frequency of these eight blood groups (as in the general population).
a. Make a table showing the probability of meeting someone in each of the eight groups.
b. For a group of 50 people, how many would you expect to have in each one of these groups?

I have gotten this info :

ABO Type Rh Type
O positive 37.4%
O negative 6.6%
A positive 35.7%
A negative 6.3%
B positive 8.5%
B negative 1.5%
AB positive 3.4%
AB negative .6%

Please help, I have 5 projects to complete by tonight in Statistics and ready to cry. TIA.


MHF Helper
Sep 2012
Hey bke0712.

Relative frequencies are just frequencies divided by other frequencies.

You should really show your attempts at an answer before getting more detailed feedback but consider what is mentioned above (and the fact that the percentages are most likely the relative frequencies).

Note that probabilities have to always be between 0 and 1 and they all must add up to 1.
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MHF Helper
Oct 2009
Probabilities are usually expressed as decimal numbers. Note that 37.4% = 37.4/100 = 0.374 etc

% means "per cent" which means "per hundred".

So 37.4 people out of 100 are O positive.

How many out of 50 would you expect to be O positive? etc.