Download 5.1 – 5.3 Review - Bryant Middle School

Statistics
5.1 – 5.3 Review
Name: ___________________
1. Find the area under the standard normal curve between z = -0.8 and z = 2.3.
2. Find the area under the standard normal curve to the right of z = -1.5.
3. Find the area under the standard normal curve to the left of z = 0.7.
Find the area of the indicated region under the standard normal curve.
4.
5.
6.
7. Use the standard normal curve to find P(0 < z < 2.25)
8. Use the standard normal curve to find P(z > -1.83)
IQ scores are normally distributed with a mean of 100 and a standard deviation of 15.
9. An individual’s IQ score is found to be 110. Find the z-score corresponding to this value.
10. An individual’s IQ score is found to be 80. Find the z-score corresponding to this value.
The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a
standard deviation of 15 days.
11. Find the probability of a pregnancy lasting more than 300 days.
12. Find the probability of a pregnancy lasting less than 250 days.
13. An airline knows from experience that the distribution of the number of suitcases that get lost
each week on a certain route is approximately normal with   15.5 and   3.6 . What is the
probability that during a given week the airline will lose less than 20 suitcases?
14. Assume that blood pressure readings are normally distributed with a mean of 120 and a
standard deviation of 8. A blood pressure reading of 145 or more may require medical attention.
What percent of people have a blood pressure reading greater than 145?
15. Assume that the heights of American men are normally distributed with a mean of 69.0 inches
and a standard deviation of 2.8 inches. The U.S. Marine Corps requires that men have heights
between 64 and 78 inches. Find the percent of men meeting these requirements.
16. Find the z-score associated with an area of 0.2810 under the standard normal curve.
17. Find the z-score for which 90% of the distribution’s area lies between –z and z.
18. Find the z-score that has 84.85% of its distribution’s area to its right.
19. Use a standard normal table to find the z-score that corresponds to the 78th percentile.
20. The scores of a history test have a mean of 65 and a standard deviation of 5. Find the test score
that corresponds to the z-score of -1.28.
21. Assume that blood pressure is readings are normally distributed with   124 and   9 . A
researcher wishes to select people for a study but wants to exclude the top and bottom 10%. What
would be the upper and lower readings to qualify people to participate in this study?
22. The times for completing one circuit of a bicycle course are normally distributed with a mean
of 82.1 minutes and a standard deviation of 4.8 minutes. An association wants to sponsor a race,
but will cut the bottom 25% of riders. In a trial run, what should be the cutoff time?