Respuesta :

Answer:

34.9% of the data in a standard normal distribution lies between x = .09 and x = 1.2.

Step-by-step explanation:

We have to find the percentage of the data in a standard normal distribution that lies between X = 0.09 and X = 1.2.

As we know that the mean and the standard deviation of a standard normal distribution is 0 and 1 respectively.

The z-score probability distribution for the standard normal distribution is given by;

                          Z  =  [tex]\frac{X-\mu}{\sigma}[/tex] = [tex]\frac{X-0}{1}[/tex]  ~ Standard normal

Now, the percentage of the data in a standard normal distribution that lies between X = 0.09 and X = 1.2 is given by = P(0.09 < X < 1.2)

        P(0.09 < X < 1.2) = P(X < 1.2) - P(X [tex]\leq[/tex] 0.09)

 

       P(X < 1.2) = P( [tex]\frac{X-0}{1}[/tex] < [tex]\frac{1.2-0}{1}[/tex] ) = P(Z < 1.2) = 0.8849

       P(X [tex]\leq[/tex] 0.09) = P( [tex]\frac{X-0}{1}[/tex] [tex]\leq[/tex] [tex]\frac{0.09-0}{1}[/tex] ) = P(Z [tex]\leq[/tex] 0.09) = 0.5359

The above probabilities are calculated by looking at the value of z = 1.2 and x = 0.09 in the z table which has an area of 0.8849 and 0.5359 respectively.

Therefore, P(0.09 < X < 1.2) = 0.8849 - 0.5359 = 0.349.