18. Suppose that the vehicle speeds at an interstate location have a normal distribution with a mean equal to 70mph and a standard deviation equal to 8mph. What is the z-score for a speed of 68mph? (2 points)
A.z=−0.35z=−0.35 B.z=−0.55z=−0.55 C.z=−0.25z=−0.25 D.z=−0.45z=−0.45 19.
The time it takes for Grade 11 students in a certain school to complete a physical fitness test is normally distributed with a mean of 15 minutes and a standard deviation of 4 minutes. If the students who get the fastest 10% completion times will be exempted from the additional gym workout sessions, what is the slowest time for a student to qualify for the exemption? (2 points)
A. 9.88 minutes B.18.36 minutes C.8.42 minutes D.11.64 minutes
20. Which of the following statements about the normal curve is FALSE?
A.The normal distribution is a continuous random probability distribution.
B. The standard normal distribution is unimodal.
C. The total area under the normal distribution is one.
D. All variables that are approximately normally distributed can be transformed into normal variables. 21. Let z1=−1.80z1=−1.80![]()
and ![]()
z2=−0.25z2=−0.25. Which among the following probabilities for z-score illustrates the area under the standard normal curve as shown at the right using ![]()
z1z1and z2z2 ?
A.P(−1.80<z<−0.25)P(−1.80<z<−0.25) B.P(z>−0.25)P(z>−0.25) C.P(−1.80>z<−0.25)P(−1.80>z<−0.25) D.P(z>−1.80)P(z>−1.80) 22.Terence's scores in Mathematics this semester were rather inconsistent. His scores are as follows: 55, 100, 95, 85, 75, 100. How many scores are within one standard deviation of the mean? (2 points)
A.5 B.6 C.3 D.4
23. Which is TRUE about the negative z- score?
A. A negative z-score means that the student’s score surpassed more than 50% of his classmates.
B. A negative z-score implies that the students scored higher than the class mean.
C. A negative z-score means that the student’s score is lower than the median.
D. A negative z-score means that the student’s score is located at the right side of the curve.
24. Find the area under the standard normal curve between z = 0 and z = – 1.05.
A. 0.1469
B. 0.4332
C. 0.3531
D.0.0668
18. Suppose that the vehicle speeds at an interstate location have a normal distribution with a mean equal to 70mph and a standard deviation equal to 8mph. What is the z-score for a speed of 68mph? (2 points)
A.z=−0.35z=−0.35 B.z=−0.55z=−0.55 C.z=−0.25z=−0.25 D.z=−0.45z=−0.45 19.
The time it takes for Grade 11 students in a certain school to complete a physical fitness test is normally distributed with a mean of 15 minutes and a standard deviation of 4 minutes. If the students who get the fastest 10% completion times will be exempted from the additional gym workout sessions, what is the slowest time for a student to qualify for the exemption? (2 points)
A. 9.88 minutes B.18.36 minutes C.8.42 minutes D.11.64 minutes
20. Which of the following statements about the normal curve is FALSE?
A.The normal distribution is a continuous random probability distribution.
B. The standard normal distribution is unimodal.
C. The total area under the normal distribution is one.
D. All variables that are approximately normally distributed can be transformed into normal variables. 21. Let z1=−1.80z1=−1.80 and
z2=−0.25z2=−0.25. Which among the following probabilities for z-score illustrates the area under the standard normal curve as shown at the right using
z1z1and z2z2 ?
A.P(−1.80<z<−0.25)P(−1.80<z<−0.25) B.P(z>−0.25)P(z>−0.25) C.P(−1.80>z<−0.25)P(−1.80>z<−0.25) D.P(z>−1.80)P(z>−1.80) 22.Terence's scores in Mathematics this semester were rather inconsistent. His scores are as follows: 55, 100, 95, 85, 75, 100. How many scores are within one standard deviation of the mean? (2 points)
A.5 B.6 C.3 D.4
23. Which is TRUE about the negative z- score?
A. A negative z-score means that the student’s score surpassed more than 50% of his classmates.
B. A negative z-score implies that the students scored higher than the class mean.
C. A negative z-score means that the student’s score is lower than the median.
D. A negative z-score means that the student’s score is located at the right side of the curve.
24. Find the area under the standard normal curve between z = 0 and z = – 1.05.
A. 0.1469
B. 0.4332
C. 0.3531
D.0.0668
