help i do not understand how to solve this question: assume that blood pressure readings are normally distributed with a mean of 111 and standard deviation of 7. A researcher wishes to select people for a study but wants to exclude the top and bottom 10 percent. What would be the upper and lower readings to qualify people to participate in the study?

Question

help i do not understand how to solve this question:   assume that blood pressure readings are normally distributed with a mean of 111 and standard deviation of 7. A researcher wishes to select people for a study but wants to exclude the top and bottom 10 percent. What would be the upper and lower readings to qualify people to participate in the study?

PsyDAG · Answer

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.10) and its Z score.

Insert ±Z into equation above and solve for score.