View the step-by-step solution to:


The following data sets are normally distributed:

a) GRE (Graduate Record Exam) individual test scores:

mean= 530 , standard deviation= 128

b) Stanford-Binet IQ scores:

mean= 100 , standard deviation= 15

c) lengths of pregnancies:

mean= 266 days , standard deviation= 16 days 

1. Find the width of the interval that spans the middle 70% of each distribution.

2. Find the cutoff for the top 12% of each distribution.


3. a) Find the percent of GRE scores that fall between 278 and 688.

b) Find the percent of pregnancies that last between 248 and 284 days.

c) Find the percent of IQ scores that fall between 117 and 121. 

Top Answer

1) a.397.3365662.6635... View the full answer

Sign up to view the full answer

Why Join Course Hero?

Course Hero has all the homework and study help you need to succeed! We’ve got course-specific notes, study guides, and practice tests along with expert tutors.

  • -

    Study Documents

    Find the best study resources around, tagged to your specific courses. Share your own to gain free Course Hero access.

    Browse Documents
  • -

    Question & Answers

    Get one-on-one homework help from our expert tutors—available online 24/7. Ask your own questions or browse existing Q&A threads. Satisfaction guaranteed!

    Ask a Question