8.08 percent of babies are born prematurely .
We have following information,
lengths of pregnancy of humans are Normally distributed.
mean of distribution ( μ ) = 268 days
standard deviations of distribution = 15 days
We shall find out the pecent of babies are born. prematurely.
Using the Normal distribution formula ,
Z = ( X - μ ) /σ
where X---> sample mean
μ --> poplution mean
putting the possble values of variables we get,
if a baby born three weaks early then he is considered as premature.
X = 21 , μ = 268 , r =
Z = ( 21-268)/ 15 = - 247/15 = - 16.4
Now, p-value corresponding to Z-value= -16.4 is
8.08..
thus for z= -16.4 , p-value will be 8.08 .. So, 8.08 percent of babies are born prematurely.
To learn more about Normal distribution, refer :
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