Select True or False 1. A random variable X is normally distributed with a mean of 150 and a variance of 36. Given that X = 120, its corresponding z− score is 5.0 __________ 2. Let z1 be a z−score that is unknown but identifiable by position and area. If the symmetrical area between −z1 and +z1 is 0.9544, the value of z1 is 2.0________ 3. The mean and standard deviation of a normally distributed random variable which has been standardized are one and zero, respectively._______

Respuesta :

Using the normal distribution, it is found that the statements are classified as:

1. False.

2. True.

3. False.

Normal Probability Distribution

In a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

  • It measures how many standard deviations the measure is from the mean.
  • After finding the z-score, we look at the z-score table and find the p-value associated with this z-score, which is the percentile of X.

Item 1:

We have that [tex]\mu = 150, \sigma = 6, X = 120[/tex], hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{120 - 150}{6}[/tex]

[tex]Z = -5[/tex]

Hence the statement is false.

Item 2:

z = 2 has a p-value of 0.9772, z = -2 has a p-value of 0.0228.

0.9772 - 0.0228 = 0.9544.

Hence the statement is true.

Item 3:

The mean is 0 and the standard deviation is 1, hence the statement is false.

More can be learned about the normal distribution at https://brainly.com/question/24663213