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#1 2006-10-18 06:45:11

abc4616
Member
Registered: 2006-10-01
Posts: 9

Normal distribution

Find the approximate value of constant c for a standard normal random variable such that:
a) For c>0, P(0<Z<c) = 0.48382
b) For c>0, P(-c<Z<c) = 0.95000

Does anyone know how to approach this?

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#2 2006-10-18 21:45:14

harish
Guest

Re: Normal distribution

Hi,
For the first one,
calculate u=[( c - mu)/sigma] which is upper bound for a normal distribution with a variable(z).
z= [( x - mu)/sigma]
where,
sigma = standard deviation
mu = mean

Using the given value, see the tables of normal distribution and find the value of u.
After we get z value, we will go in reverse.

Then,

c will be [(z*sigma)/(c- mu)]




For the second one,
since the normal distribution has symmetry,

that will become 2*P[0<x<c]=0.95

P[0<x<c]=0.95/2=.475

And it will be solved as the earlier one.

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