The number of cell phone minutes used by high school seniors follows a normal distribution with a mean of 500 and a standard deviation of 50.What is the probability that a student uses more than 580 minutes?
A)0.152
B)0.0548
C)0.848
D)0.903
E)None of the above

Question

Quizplus · Accepted Answer

We need to find the area to the right of 580 in a normal distribution with a mean of 500 and a standard deviation of 50. 
Using the z-score formula: 
z = (x - μ) / σ = (580 - 500) / 50 = 1.6
Using a standard normal distribution table, the area to the right of 1.6 is 0.0548. Therefore, the probability that a student uses more than 580 minutes is 0.0548.

The Number of Cell Phone Minutes Used by High School