A certain university maintains a colony of male mice for research purposes. The ages of the mice are normally distributed with a mean of 60 days and a standard deviation of 5.2. Assume you randomly sample one mouse from the colony. The probability his age will be greater than 68 is _________.
A) 0.4382
B) 0.0618
C) 0.9382
D) 0.0630

Question

Quizplus · Accepted Answer

We need to find the probability that a randomly selected mouse from the colony will have an age greater than 68. 
We can standardize the variable using the formula: (x - μ)/σ, where x is the value we're interested in, μ is the mean, and σ is the standard deviation. 
So, (68 - 60)/5.2 = 1.54 
Using a standard normal table or calculator, we can find the probability that a standard normal variable is greater than 1.54, which is 0.0618. Therefore, the answer is B.

A Certain University Maintains a Colony of Male Mice for Research