The amount of Jen's monthly phone bill is normally distributed with a mean of $55 and a standard deviation of $8.Draw and label the Normal model for Jen's monthly phone bill.In what interval would you expect the central 68% of bills to be found?
A) ;$31 to $79
B) ;$39 to $71
C) ;$47 to $71
D) ;$47 to $63
E) ;$39 to $63

Question

The amount of Jen's monthly phone bill is normally distributed with a mean of $55 and a standard deviation of $8.Draw and label the Normal model for Jen's monthly phone bill.In what interval would you expect the central 68% of bills to be found?
A) ;$31 to $79 
B) ;$39 to $71 
C) ;$47 to $71 
D) ;$47 to $63 
E) ;$39 to $63

Quizplus · Accepted Answer

To draw the Normal model, we start at the mean of $55 and then move one standard deviation in each direction to get to $47 and $63. This interval represents one standard deviation from the mean, which encompasses approximately 68% of the observations in a Normal distribution. Therefore, we expect the central 68% of Jen's monthly phone bills to fall between $47 and $63. Choice D is the only option that includes this interval.

The Amount of Jen's Monthly Phone Bill Is Normally Distributed