Cancer odds

[Uglyowl]

Here is the situation.

I work in an office with 75 people who have pretty much all been there for the past 7 years.

Average age: 40
Odds of getting cancer between birth and 40: 1 in 60 get cancer before the age of 40.
We have had 4 confirmed cases of cancer (all under the age of 40) in our office in the past 5 years with 2 more being looked at a possibilities.

Assuming each year there is an equal chance to get cancer what are the odds of having 4 people, 5 people, 6 people get
cancer in a 5 year period.

What is the expected rate?

Thanks!

[blank frank]

[ QUOTE ]
Here is the situation.

I work in an office with 75 people who have pretty much all been there for the past 7 years.

Average age: 40
Odds of getting cancer between birth and 40: 1 in 60 get cancer before the age of 40.
We have had 4 confirmed cases of cancer (all under the age of 40) in our office in the past 5 years with 2 more being looked at a possibilities.

Assuming each year there is an equal chance to get cancer what are the odds of having 4 people, 5 people, 6 people get
cancer in a 5 year period.

[/ QUOTE ]

Well, that's not how the question should be asked, IMHO. I would ask what are the odds that more than 4 people get cancer in five years. Now, if you assume an even rate across years, each person has about a 1 in 480 chance of getting cancer in that period. If you have 75 people, the odds of four or more getting cancer in a five year period are about 1 in 49,300.

The thing is, I'm not sure the assumption is warranted. Different cancers occur more frequently at different times in life, and I would not be surprised at all if they concentrate at older ages. Take that 1 in 60 chance, but assume instead that you are twice as likely to get cancer around 40 as in an average year. Now the odds of four or more people getting cancer drop to about 1 in 3,500. If you triple it, it drops to about 1 in 775.

Then you have to ask yourself, how many groups of office workers like yours are there in the US?

[Uglyowl]

Thanks for taking the time in your response. Each person diagnosed was in their mid to late 20's.

While the odds are high, they are not as astronomical as I would have imagined. I am sure if we add a 5th or 6th, then maybe something needs to be looked at closer.

[kelvin474]

[ QUOTE ]
I am sure if we add a 5th or 6th, then maybe something needs to be looked at closer.

[/ QUOTE ]

This statement makes little sense regardless of the topic.