Q:

The weights of newborn babies are distributed​ normally, with a mean of approximately 105 oz and a standard deviation of 10 oz. If a newborn baby is selected at​ random, what is the probability that the baby weighs more than 75 ​oz

Accepted Solution

A:
Answer: 0.9987Step-by-step explanation:Given : The weights of newborn babies are distributed​ normally, with a mean of approximately 105 oz and a standard deviation of 10 oz. i.e. [tex]\mu=105\ oz[/tex]  and [tex]\sigma= 10\ oz[/tex]Let x represents the weights of newborn babies.If a newborn baby is selected at​ random, then the probability that the baby weighs more than 75 ​oz will be :-[tex]P(x>75)=P(\dfrac{x-\mu}{\sigma}>\dfrac{75-105}{10})\\\\ =P(z>-3 )=P(z<3)\ \ \ [\because\ P(Z>-z)=P(Z<z)][/tex][tex]=0.9987[/tex]   [using z-value table]Hence, the required probability = 0.9987