College

Nick has collected data showing that the body weights of the forty students in a class have a normal distribution.

What is the probability that a randomly selected student has a body weight greater than 169 pounds, given that the mean is 142 pounds and the standard deviation is 9 pounds?

Use the empirical rule.

Answer :

Answer:

0.0015 is he probability that a randomly selected student has a body weight of greater than 169 pounds.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 142 pounds

Standard Deviation, σ = 9 pounds

We are given that the distribution of body weights is a bell shaped distribution that is a normal distribution.

Empirical Rule:

  • The empirical rule states that for a normal distribution 68% falls within the first standard deviation from the mean, 95% within the first two standard deviations from the mean and 99.7% within three standard deviations of the mean.

P( body weight of greater than 169 pounds)

[tex]169 = 142 + 3(9) = \mu + 3\sigma\\115 = 142-3(9) = \mu - 3\sigma[/tex]

According to empirical rule, 99.7% within three standard deviations of the mean.

Thus, we can write:

P( body weight of greater than 169 pounds)

[tex]\displaystyle\frac{1-P(\text{Body weight between 115 and 169})}{2}\\\\= \frac{1-0.997}{2} = 0.0015[/tex]

0.0015 is he probability that a randomly selected student has a body weight of greater than 169 pounds.

Answer:

mean=142

169-142/9

P(x>169)=1-.997/2

=.15

Step-by-step explanation: