PSY 309W Exam 4
What is the variance for the following population of scores? Scores: 5, 2, 5, 4
1.5
What is the value of SS (sum of squared deviations) for the following population? Population: 1, 1, 1, 5
12
What is the value of SS (sum of squared deviations) for the following sample? Sample: 2, 3, 4, 7
14
A population has sum of squared deviations, SS = 100 and variance, s 2 = 4. What is the value of the standard deviation of the population?
2
A population of N = 5 scores has ΣX = 20 and ΣX 2 = 100. For this population, what is the value of SS (sum of squared deviations)?
20
A population has sum of squared deviations, SS = 100 and variance, s 2 = 4. How many scores are in the population?
25
What is the value of SS for the following set of scores? Scores: 8,3,1
26
A population of scores has µ = 80. In this population, a score of X = 86 corresponds to z = +2.00. What is the population standard deviation?
3
A sample of n = 25 scores has mean M = 20 and variance s2 = 9. What is the sample standard deviation?
3
What is the value of SS (sum of squared deviations) for the following sample? Sample: 1, 1, 1, 3
3
A population of N = 6 scores has Σ X = 12 and Σ X2 = 54. What is the value of SS for this population?
30
The sum of the squared deviation scores is SS = 20 for a sample of n = 5 scores. What is the variance for this sample?
5
For a population with µ = 80 and σ = 10, what is the X value corresponding to z = -0.50?
75
For a particular sample of size n=10, the largest distance (deviation) between a score and the mean is 11 points. The smallest distance between a score and the mean is 4 points. Therefore, the standard deviation will be ____.
Between 4 and 11
In N = 25 games last season, the college basketball team averaged µ = 76 points with a standard deviation of σ = 6. In their final game of the season, the team scored 89 points. Based on this information, the number of points scored in the final game was ____.
Far Above Average
Last week Sarah had exams in Math, Spanish and English. On the Math exam, the mean was µ = 40 with σ = 5 and Sarah had a score of X = 45. On the Spanish exam, the mean was µ = 60 with s = 8 and Sarah had a score of X = 68. On the English exam, the mean was µ = 70 with s = 8 and Sarah had a score of X = 78. For which class should Sara expect the better grade?
Grades are the same
A sample with M = 85 and s = 12 is transformed into z-scores. After the transformation, what are the values for the mean and standard deviation for the sample of z-scores?
M=0 and s=1
For a sample of n = 30 scores, X = 45 corresponds to z = 1.50 and X = 40 corresponds to z = +1.00. What are the values for the sample mean and standard deviation?
M=30 and s=10
What are the values for SS and variance for the following sample of n = 3 scores? Sample: 1, 4, 7
SS=18 and variance=9
What are the values for SS (sum of squared deviations) and variance for the following sample of n = 4 scores? Sample: 1, 1, 0, 4
SS=9 and Variance=3
What is the value of SS (sum of squared deviations) for the following set of scores? If the scores constitute a population, what is the population standard deviation, s? Scores: 1, 1, 4, 0.
SS=9 and s=2.25
The process of transforming every x value in a distribution into a corresponding z-score to create a distribution of z-scores is called a z-score transformation.
True
The range and the standard deviation are both measures of spread.
True
The range is usually considered to be a relatively crude measure of variability.
True
Variability provides a quantitative measure of the difference between scores in a distribution.
True
A population distribution has σ = 6. What position in this distribution is identified by a z-score of z = +2.00?
Twelve points above the mean
A distribution with µ = 35 and s = 8 is being standardized so that the new mean and standard deviation will be µ = 50 and s = 10. In the new, standardized distribution your score is X = 45. What was your score in the original distribution?
X=31
In a population of scores, X = 83 corresponds to z = -0.50 and X = 93 corresponds to z = +2.00. What are the values for the population mean and standard deviation?
m=85 and s=4
Which of the following symbols identifies the sample variance?
s^2
Which of the following represents the deviation score?
x-u
Which of the following z-score values represents the location closest to the mean?
z=+0.50
Which of the following symbols identifies the population standard deviation?
σ
On an exam with μ = 52, you have a score of X = 56. Which of the following values for the standard deviation would give you the highest position in the class distribution?
σ = 2
A population has μ = 50. What value of σ would make X = 55 a more central, representative score in the population?
σ = 20
Given a population with M=60, which of the following values for the population standard deviation would cause X=68 to have the most extreme position in the distribution?
σ=2
If sample variance is computed by dividing SS by df = n - 1, then the average value of the sample variances from all the possible random samples will be ____ the population variance.
Exactly Equal To
For a sample with s = 12, a score of X = 73 corresponds to z = 1.00. What is the sample mean?
M=61
Last week, Sarah had exams in Math, Spanish, and English. On the Math exam, the mean was µ = 30 with s = 5, and Sarah had a score of X = 45. On the Spanish exam, the mean was µ = 60 with s = 8 and Sarah had a score of X = 68. On the English exam, the mean was µ = 70 with s = 8 and Sarah had a score of X = 70. For which class should Sara expect the better grade?
Math
A population of N = 5 scores has SS = 20 and σ 2 = 4. If the 5 scores were a sample, the value of SS would still be 20 but the variance would be s2 = 5.
True
A population with SS = 90 and a variance of 9 has N = 10 scores.
True
A sample with a variance of 25 has a standard deviation equal to 5 points.
True
A score with a value less than or equal to the mean will have a z-score that is less than or equal to zero.
True
After a researcher multiplies every score in a sample by 2, the standard deviation is found to be s = 10. The original sample had a standard deviation of s = 5.
True
If two individuals in the same population have identical X scores, they also will have identical z - scores.
True
In a population with s=4, a score of X=48 corresponds to z=1.50. The mean for the population is µ=42.
True
It is easier to see the mean difference between two samples if the sample variances are small.
True
On an exam, Tom scored 12 points above the mean and had a z-score of +2.00. The standard deviation for the set of exam scores must be s = 6.
True
Standardized scores are "simple" values for the mean and standard deviation that do not change any individual's location within the distribution.
True
Given a population of N scores, the sum of the deviation scores is equal to N.
False
If the population variance is 5, then the population standard deviation is σ = 25.
False
A positive deviation always indicates a score that is less than the mean.
False
For a population, a deviation score is computed as X - μ.
True
A population of scores has µ = 50 and σ = 5. If every score in the population is multiplied by 3, then what are the new values for the mean and standard deviation?
µ = 150 and σ = 15
A population has µ = 50 and σ = 5. If 10 points are added to every score in the population, then what are the new values for the mean and standard deviation?
µ = 60 and σ = 5
In a population with σ = 8, a score of X = 44 corresponds to a z-score of z = -0.50. What is the population mean?
μ = 48
You have a score of X = 65 on an exam. Which set of parameters would give you the best grade on the exam?
μ = 60 and σ = 5
You have a score of X = 75 on a statistics exam. The mean score for the class on the exam is μ = 70. Which of the following values for the standard deviation would give you the highest position within the class?
σ = 1
Which set of scores has the smallest standard deviation?
145, 143, 145, 147
A sample of n = 7 scores has SS = 42. The variance for this sample is s2 = 6.
False
A sample of n = 20 scores has a mean of M = 45 and a standard deviation of s = 8. In this sample, what is the z-score corresponding to X = 57?
z=1.50
A population of N = 100 scores has mean µ = 30 and standard deviation σ = 4. What is the population variance?
16
For a sample of n = 16 scores, how many scores are used to calculate the sample variance?
16
What is the value of SS for the following set of sample scores? Scores: 0, 1, 4, 5
17
A sample consists of n = 16 scores. How many of the scores are used to calculate the range?
2
The sum of the squared deviation scores is SS = 20 for a population of N = 5 scores. What is the variance for this population?
4
A sample of n = 8 scores has SS = 50. If these same scores were a population, then the SS value for the population would be ____.
50
A population of scores has µ = 44. In this population, a score of X = 40 corresponds to z = -0.50. What is the population standard deviation?
8
For a population with µ = 100 and σ = 20, what is the X value corresponding to z = -0.75?
85
If sample variance is computed by dividing SS by df=n-1, then the average value of the sample variance from all the possible random samples will be _____ the population variance.
Exactly Equal to
For a population with a mean of μ = 40, a score of X = 37 corresponds to z = -0.50. The standard deviation for the population is s = 3.
False
For a population with a mean of μ = 80 and a standard deviation of σ = 12, a score of X = 77 corresponds to z = -0.50.
False
For a population with µ = 70 and σ = 5, about 95% of the individuals will have scores between X = 65 and X = 75.
False
For a population with μ = 30, a score of X = 24 corresponds to z = -2.00. The standard deviation for the population is s = 6.
False
For a sample with a standard deviation of s = 6, a z-score of z = -1.50 corresponds to a location that is 9 points above the mean.
False
For a sample with a standard deviation of s = 8, a score of X = 42 corresponds to z = -0.25. The mean for the sample is M = 40.
False
If you have a score of X = 76 on an exam with μ = 70, you should expect a better grade if σ = 10 than if σ = 5.
False
In a sample of n = 40 scores, X = 31 corresponds to z = -1.50 and X = 39 corresponds to z = +0.50. The sample mean is M = 36.
False
Multiplying every score in a sample by 3 will not change the value of the standard deviation.
False
For an exam with a mean of M = 74 and a standard deviation of s = 8, Mary has a score of X = 80, Bob's score corresponds to z = +1.50, and Sue's score is located above the mean by 10 points. If the students are placed in order from smallest score to largest score, what is the correct order?
Mary,Sue,Bob
The smallest score in a population is X = 5 and the largest score is X = 10. Based on this information, you can conclude that the____.
Standard Deviation is smaller than 5
Any individual with a positive z-score has a score greater than the mean.
True
Because all z-score distributions have the same mean and standard deviation, the z-score distribution is called a standardized distribution.
True
For a population of exam scores, a score of X = 83 corresponds to z = +0.50 and a score of X = 89 corresponds to z = +1.50. The population mean is μ = 80.
True
For a population with a mean of μ = 80, any score greater than 80 will have a positive z-score.
True
For a population with a standard deviation of s = 12, a z-score of z = +0.50 corresponds to a score that is above the mean by 6 points.
True
For a sample with M = 20 and s = 1, a score of X = 17 would be considered an extremely low score.
True
For a sample with M=40 and s=4, about 95% of the individuals will have scores between X=32 and X=48.
True
For a sample with a mean of M = 50 and a standard deviation of s = 10, a z-score of z = +2.00 corresponds to X = 70.
True
For a sample with a mean of M = 76, a score of X = 72 corresponds to z = -0.50. The sample standard deviation is s = 8.
True
For any distribution of scores, the location identified by z = +1 and the location identified by z = -1 are exactly the same distance from the mean.
True
If the population standard deviation is 4, then the variance will be σ2 = 16.
True
A population of scores has µ = 50 and σ = 5. If every score in the population is multiplied by 3, then what are the new values for the mean and standard deviation?
µ = 150 and σ = 15
Which of the following is true for most distributions?
Around 70% of the scores will be located within one standard deviation of the mean.
Under what circumstances is a score that is 15 points above the mean an extreme score relatively far from the mean?
When the population standard deviation is much smaller than 15
