Assume that the heights of adult caucasian women have a mean of 63.6 inches and a standard deviation of 2.5 inches. if 100 women are randomly​ selected, find the probability that they have a mean height greater than 63.0 inches. round to four decimal places.

Respuesta :

The probability that the mean height is greater than 63 in will be given by:
z-score
z=(x-μ)/σ
z=(63.6-63)/2.5
z=0.24
The probability will be:
P(X≥63)=1-(P=z)
=1-0.6331
=0.3669

The probability that they have a mean height greater than 63.0 inches will be 0.9918

Explanation

The heights of adult Caucasian women have a mean of 63.6 inches and a standard deviation of 2.5 inches. That means,  [tex]\mu = 63.6[/tex] and [tex]\sigma = 2.5[/tex]

As 100 women are randomly​ selected, so the sample size[tex](n)[/tex] = 100

The formula for finding the z-score is......

[tex]z= \frac{x-\mu}{(\frac{\sigma}{\sqrt{n}})}[/tex]

So, the z-score of a mean height for 63.0 inches will be......

[tex]z(x=63.0) = \frac{63.0-63.6}{(\frac{2.5}{\sqrt{100}})}=\frac{-0.6}{0.25}=-2.4[/tex]

According to the normal distribution table,  [tex]P(z<-2.4)= 0.0082[/tex]

So, [tex]P(x>63.0)=P(z>-2.4)= 1-P(z<-2.4)= 1-0.0082=0.9918[/tex]

Thus, the probability that they have a mean height greater than 63.0 inches will be 0.9918