need some help in Statics home work assigment

[alsayyed]

Pharmaceutical  reseacher  working on cure baldness noticed that middle-age who are balding at the crown of their head have a 45% probability of suffering a heart attack over the next decade. In a sample of 100 middle  age balding men. What are the following probailities?
a. More than 50 will suffer a heart attack in the next decade
b. fewwer that 44 will suffer a heart attack in the next decade.
c. exactly 45 will suffer a heart attack in the next decade

[SwampDonkey]

Looks like a binomial distribution and it's a lot of writing long hand. My text has a table of up to n=15, p=0.90

But the first solution looks like this......

P (x>50) = 100! x ( 9 )⁵¹ x (1 - 9 )^100-51
              51!49!  (20)      (     20)
               = 0.0386 or 3.86%

Note 9/20 = 0.45 = p in your question, just wanted to use fractions. ;)

Use Microsoft's Excel BINOMDIST function.

The second would be:

P (0<= x <=43) = 1-0.0785 = 0.9215 Note I calculated the binomial distribution of 44 or greater heart attacks and subtracted from 1. We know that it would be a very high probability.

The third would be a cumulative binomial distribution

P (x=45) = 0.54

You can also use this web link

http://stattrek.com/Tables/Binomial.aspx


Anyone else want to chime in?  :P

[woodmills1]

that looks like how I would solve it

[TerryB]

Wow SwampDonkey, is there anything you don't know?   


BTW, it looks more like statistics than statics.

[sprucebunny]

c. if their theory is exactly right.

[pigman]

I think you are right Terry. I thought it was going to be a question about forces on a bridge or something. I do know a lot about baldness, but little about statistics. :-\

[DanG]

Alsayyed, let me first say that I am more than impressed with the progress you have made in communicating in English.  You have done very well! 8) 8)

I know nothing of statistics, and I am puzzled by the people who seem to understand them.  I am more of a logical type.  From the information given in your problem, I would say that exactly 45 of the 100 would suffer a heart attack within the next decade, however, reality has a factor in it as well.  My logical mind tells me that a few of them would die from other causes before they had a heart attack, so that the number of victims would decrease to less than 44.  You must determine if the question is asked about 100 balding men who do not die from some other cause, or 100 balding men in general.  In other words, are you to consider all of the statistics concerning middle aged balding men, or just the chance of them having a heart attack if nothing else happens?

[SwampDonkey]

Wow SwampDonkey, is there anything you don't know?   

Well, it's more like, there's a question posed and lets see if we can help. :D

Don't think for one moment I didn't have to dig out the Stats book to energize the brain cells.  ;D :D :D

[Warbird]

So this begs the next question... what is the probability that one of us FF members would still have an old stats book laying around and enough memory left to know what to look for?  ;) ;D

[Roxie]

Since you said, "home work assignment" I'm going to assume that we don't need to know all the other statistics on the death of balding men.  I also don't need a stats book to conclude that 3 is the correct answer.

What grade homework assignment are we talking bout? 

[SwampDonkey]

I think he got scared out of his wig with the math. ;D  :D

[Lanier_Lurker]

Yep, when I read statics I was thinking something totally different - as in physics, not statistics.

[Jeff]

I have no plans on going bald, so I can't relate. I have threatened to shave my head though, and if I do, maybe I'll take a stab and say exactly 45 too.

[SwampDonkey]

It's not multiple choice bub. :D :D ;) As far as the hair, that ain't either. When both your grand dad's went bald, you got a slim chance of keeping your rug. 

How many trees did ya dibble into the ground today? ;D

[Jeff]

80 Problem was choosing where I wanted them.  Most are not trees, but Bushes.  High bush cranberry, black eldeberry and silky dogwood. The rest were Bur Oak Which are certainly for the next owner, as it will be 35 years or more before they have acorns.

[SwampDonkey]

I would think there would be tons of high bush cranberry around. They seem to do well here under aspen on the wetter sites. V. trilobum is our high bush, but there are a couple other species that aren't much different. I have one on the the lawn, but the back yard has quite a few where the old orchard was. The grouse sure like'em and squirrels to. Our wild elders are beginning to flower now, I think it's red-berried elder, S. racemosa. The stuff grows on the bank of most any bull dozed woods road.