1. If you have a score of X = 75 on an exam, which set of parameters would give
ID: 3023334 • Letter: 1
Question
1. If you have a score of X = 75 on an exam, which set of parameters would give you the highest position within the class?
a. = 70 and = 5
b. = 70 and = 10
c. = 60 and = 10
d. = 60 and = 5
2. A population of scores has = 50 and = 12. If you subtract five points from every score in the population, then the value for the new standard deviation will be _______.
a. insufficient information, cannot be determined
b. 7
c. 12
d. 2.4
3. After 10 points are added to every score in a sample, the mean and standard deviation are found to be M = 85 and s = 15. What were the original values for the mean and standard deviation?
a. M = 85 and s = 15
b. M= 75 and s = 5
c. M= 85 and s = 5
d. M= 75 and s = 15
4. A population has = 40 and = 8. If each score is divided by 2, then the new standard deviation will be
a. 16
b. 4
c. insufficient information, cannot be determined
d. 8
5. Sample variance provides an unbiased estimate of the population variance. The term unbiased means _______.
a. For any sample, the sample variance will equal the population variance.
b. For large samples, the sample variance will equal the population variance.
c. If sample variance is computed for many samples, the average sample variance will equal the population variance.
d. None of the other choices is correct.
Explanation / Answer
1. If you have a score of X = 75 on an exam, which set of parameters would give you the highest position within the class?
a. = 70 and = 5
b. = 70 and = 10
c. = 60 and = 10
d. = 60 and = 5
z=(75-70)/5 =1,
z=(75-70)/10 =0.5
z=(75-60)/10 =1.5,
z=(75-60)/5 =3,
2. A population of scores has = 50 and = 12. If you subtract five points from every score in the population, then the value for the new standard deviation will be _______.
a. insufficient information, cannot be determined
b. 7
c. 12
d. 2.4
(Adding or subtracting a constant value, c, to a random variable does not change the variance, because the expectation (mean) increases or decreases by the same amount.)
3. After 10 points are added to every score in a sample, the mean and standard deviation are found to be M = 85 and s = 15. What were the original values for the mean and standard deviation?
a. M = 85 and s = 15
b. M= 75 and s = 5
c. M= 85 and s = 5
d. M= 75 and s = 15
4. A population has = 40 and = 8. If each score is divided by 2, then the new standard deviation will be
a. 16
b. 4
c. insufficient information, cannot be determined
d. 8
5. Sample variance provides an unbiased estimate of the population variance. The term unbiased means _______.
a. For any sample, the sample variance will equal the population variance.
b. For large samples, the sample variance will equal the population variance.
c. If sample variance is computed for many samples, the average sample variance will equal the population variance.
d. None of the other choices is correct.
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