Statistics
Unit 5 Review
Find the indicated area:
1. to the left of z = -0.34
Name: ________________________________
The weight of adult male English Bulldogs is normally distributed with a
mean of 52 pounds and a standard deviation of 8 pounds.
2. to the right of z = -1.23
12. Find the probability that a bulldog’s weight is less than 46 pounds.
3. in between z = -0.45 and 1.20
13. Find the probability that a bulldog’s weight is between 48 and 53
pounds.
4. to the left of z = -1.65 or to the right of z = 1.2
14. Find the probability that a bulldog weighs more than 62 pounds.
Find the indicated probability:
5. P(z > 1.16)
6. P(z < -1.45)
7. P( -1.27 < z < 2.11)
8. P(z < -0.34 or z > 2.16)
A study found the mean migration distance of blue whales to be normally
distributed with a mean of 1500 miles and a standard deviation of 225
miles.
9. Find the probability that a randomly selected blue whale migrates a
distance less than 1200 miles.
10. Find the probability that a randomly selected blue whale migrates a
distance more than 1650 miles.
11. Find the probability that a randomly selected blue whale migrates a
distance between 1250 and 1700 miles.
Find the z-score that corresponds to the cumulative area or percentile:
15. 0.3854
16. 0.8106
17. P18
18. P64
The braking distance of the Ford Focus is normally distributed with a mean
of 44 yds and a standard deviation of 3 yds.
19. Find the braking distance that corresponds to a z-score of 1.6
20. What braking distance represents the 56th percentile?
21. What is the shortest braking distance that is in the top 20%?
The consumption of milk by people in the United States in a recent year
was normally distributed. µ = 35.5 gallons and σ = 9.6 gallons. Random
samples of size 40 are drawn from this population.
22. What is the mean of the sampling distribution?
23. What is the standard error of the sampling distribution?
A study found the mean migration distance of blue whales to be normally
distributed with a mean of 1500 miles and a standard deviation of 225
miles. A sample of 17 whales is randomly selected.
24. Find the probability that the mean of the migration distance is less
than 1200 miles.
25. Find the probability that the mean of the migration distance is more
than 1650 miles.
26. Find the probability that the mean migration distance is between
1250 and 1700 miles.
The mean annual salary for postal workers is $45,300. A random sample
of size 35 is drawn from this population. σ = $1900.
27. What is the probability that the mean annual salary is less than
44,000?
28. What is the probability that the mean annual salary is more than
47,000?
29. What is the probability that the mean annual salary is between
$43,500 and $49,000?
30. What is the probability that one randomly selected postal worker
has an annual salary more than $48,200?