# Problem on normal/gaussian distribution sampling

• Jul 3rd 2010, 06:43 PM
gkraju
Problem on normal/gaussian distribution sampling
Find the probability of picking up four consecutive individuals of weight greater than 70kg from a population that is normally distributed with mean weight at 60 kg and standard deviation of 5 kg ?

I solved this by calculating Z = (70 - 60 )/ 5
(from formual z = (X- mean)/std dev )

hence z = 2

then taking the area from standard table, the area to the right of 2.

this is probability of picking up person of weight greater than wt of 70kg

but how to make it applicable for picking up four consecutive individuals ?
• Jul 3rd 2010, 07:44 PM
pickslides
Quote:

Originally Posted by gkraju
but how to make it applicable for picking up four consecutive individuals ?

More information is required here, what is the dist of X where X = probability of picking up consecutive individuals?

Then find \$\displaystyle P(X=4)\$ where \$\displaystyle p= P(Z>2)\$
• Jul 3rd 2010, 08:28 PM
matheagle
\$\displaystyle p^4\$ this is binomial whre you want 4 successes in 4 trials,
the chance of one success is that p
AND these trials need to be independent