Standard Normal Distribution (mean is 0 and standard deviation is 1). Find the score that separates the lowest 98% from the highest 2%.
- 2.05
2.05
-1.95
1.95
2. Multiple Choice
5 minutes
1 pt
6.2: Uniform distribution: Suppose your phone battery can last anywhere between 2 hours and 8 hours depending on use. If the amount of time it lasts is distributed uniformly, what is the probability that the battery lasts less than 4 hours?
1/6
1/4
1/3
1/2
3. Multiple Choice
5 minutes
1 pt
6.2: Standard Normal Distribution (mean is 0 standard deviation is 1). For a randomly selected subject, find the probability of a score between 1.37 and 2.42.
0.078
0.785
0.223
0.023
4. Multiple Choice
5 minutes
1 pt
6.3: Non-Standard Normal Distribution. IQ scores are normally distributed with mean 100 and standard deviation 15. Find the probability of randomly selecting an IQ score above 90.
0.683
0.748
0.715
0.796
5. Multiple Choice
5 minutes
1 pt
6.3: Non-Standard Normal Distribution. IQ scores are normally distributed with a mean of 100 and standard deviation 15. Find the IQ score separating the bottom 85% from the top 15%.
135
125
120
115
6. Multiple Choice
5 minutes
1 pt
6.5 CLT: Red blood cell counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382. Find the probability that one randomly selected woman has a red blood cell count above 5.4.
0.150
0.0156
0.215
0.0237
7. Multiple Choice
5 minutes
1 pt
6.5 CLT: Red blood cell counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382. What percentage of women have red blood cell counts in the normal range from 4.2 to 5.4?
82.3%
77.8%
72.6%
68%
8. Multiple Choice
5 minutes
1 pt
6.5 CLT: Red blood cell counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382. If 25 women are randomly selected, find the probability that the mean of their red blood cell counts is less than 4.444.
0.409
0.0409
0.368
0.0368
9. Multiple Choice
5 minutes
1 pt
6.2: z-alpha notation (shade right): Using z-alpha notation, find the z-score for z (sub).45:
0.145
0.126
0.137
0.189
10. Multiple Choice
5 minutes
1 pt
6.7 Binomial: Use the continuity correction and describe the region of the normal distribution that corresponds to the probability of exactly 44 green marbles.
The area between 43.5 and 45.5
The area between 43.5 and 44
The area between 43.5 and 44.5
The area between 44 and 44.5
11. Multiple Choice
5 minutes
1 pt
6.7 Binomial: Estimate the indicated probability by using the normal distribution as an approximation to the binomial distribution with n = 18 and p = 0.30. Estimate P(exactly 6).
0.124
0.102
0.158
0.194
12. Multiple Choice
5 minutes
1 pt
6.3 Non-Standard Normal Distribution: A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. Find P60, the score which separates the lower 60% from the top 40%.
187.5
212.7
207.8
211.3
13. Multiple Choice
5 minutes
1 pt
6.7 Binomial: For the binomial distribution with the given values for n and p, state whether or not it is suitable to use the normal distribution as an approximation: n = 24 and p = 0.6
Yes - normal approximation is suitable.
No - normal approximation is not suitable.
14. Multiple Choice
5 minutes
1 pt
6.2 Uniform distribution: Using the uniform density curve shown, what is the probability that the random variable x has a value greater than 5? (Probability = Area of a Rectangle)
0.325
0.500
0.250
0.375
15. Multiple Choice
5 minutes
1 pt
6.3 z-scores: Scores on a history test have an average of 80 with a standard deviation of 6. What is the z-score for a student who earned a 75 on the test? (Use the formula solve for z)
-0.83
0.83
-0.17
0.17
16. Multiple Choice
5 minutes
1 pt
6.3 z-scores: The temperature is recorded at 60 airports in a region. The average temperature is 67 degrees Fahrenheit with a standard deviation of 5 degrees. Given a z-score of -0.2, what is the temperature? (Use formula, solve for x)
65
68
67
66
17. Multiple Choice
5 minutes
1 pt
6.6 Histogram: Can the mean of this sample be treated as a value from a population having a normal sample? Why or why not? 50 55 61 67 70 53 57 64 68 59
Yes, the histogram shows a normal distribution.
No, the histogram is not normal and n < 30.
No, the histogram is not normal and n > 30.
Yes, the histogram is not normal and n > 30.
18. Multiple Choice
5 minutes
1 pt
6.7 Binomial: There is an 80% chance that an employer will check the educational background of a job applicant. Sixty-four job applicants are randomly selected. What is the probability that more than 50 applicants will have their background checked?
0.702
0.528
0.673
0.587
19. Multiple Choice
30 seconds
1 pt
In a factory, the weight of the concrete poured into a mold by a machine follows a normal distribution with a mean of 1150 pounds and a standard deviation of 22 pounds. Approximately 95% of molds filled by this machine will hold weights in what interval?
1084 to 1216 pounds
1106 to 1150 pounds
1106 to 1194 pounds
1128 to 1172 pounds
20. Multiple Choice
5 minutes
1 pt
If heights of 3rd graders follow a normal distribution with a mean of 52 inches and a standard deviation of 2.5 inches, what is the z score of a 3rd grader who is 47 inches tall?