Ch. 4 Quiz 4 (PSYC, 2013, NWACC)
Q: What are the values for SS and variance for the following sample of n = 4 scores? Sample: 1, 1, 0, 4
SS = 9 and variance = 3
Q: What is the value of SS for the following set of scores? Scores: 1, 1, 4, 0
9
Q: One sample is selected to represent scores in treatment 1 and a second sample is used to represent scores in treatment 2. Which set of sample statistics would present the clearest picture of a real difference between the two treatments?
M1 = 36, M2 = 40, and both variances = 6
T/F: A sample with a variance of 25 has a standard deviation equal to 5 points.
True
Q: What is the value of SS (sum of squared deviations) for the following sample? Sample: 1, 3, 2, 2
2
Q: What is the range for the following set of scores? Scores: 5, 7, 9, 15
10 or 11 points
Q: What is the value of SS (sum of squared deviations) for the following population? Population: 1, 1, 1, 5
12
Q: In a population of N = 10 scores, the smallest score is X = 8 and the largest is X = 20. What is the range for this population?
12-13
Q: A population of N = 100 scores has m = 30 and s = 4. What is the population variance?
16
Q: A population of N = 5 scores has SX = 20 and SX2 = 100. For this population, what is the value of SS?
20
Q: A sample of n = 4 scores has SX = 8 and SX2 = 40. What is the value of SS for this sample?
24
Q: A population has SS = 100 and s2 = 4. How many scores are in the population?
25
Q: What is the value of SS for the following set of scores? Scores: 8, 3, 1.
26
Q: What is the value of SS (sum of squared deviations) for the following sample? Sample: 1, 1, 1, 7
27
Q: A population of N = 6 scores has SX = 12 and SX2 = 54. What is the value of SS for this population?
30
Q: All the possible samples of n = 3 scores are selected from a population with m = 30 and s = 5 and the mean is computed for each of the samples. If the average is calculated for all of the sample means, what value will be obtained?
30
Q: A population of N = 10 scores has a standard deviation of s = 2. What is the value of SS, the sum of the squared deviations, for this population?
40
Q: Which of the following is true for most distributions?
Around 70% of the scores will be located within one standard deviation of the mean.
T/F: A positive deviation always indicates a score that is less than the mean.
False
T/F: A sample of n = 6 scores has SS = 30 and s2 = 6. If the 6 scores were a population, the value of SS would still be 30, but the variance would be s2 = 5.
False
T/F: A sample with SS = 40 and a variance of 8 has n = 5 scores.
False
T/F: After a researcher adds 5 points to every score in a sample, the standard deviation is found to be s = 10. The original sample had a standard deviation of s = 5.
False
T/F: For a population of scores, the sum of the deviation scores is equal to N.
False
T/F: For a sample with M = 20 and s = 4, a score of X = 17 would be considered an extremely low score.
False
T/F: If a sample of n = 6 scores has SX = 30 and SX2 = 200, then SS = 20.
False
T/F: If the population variance is 4, then the standard deviation will be s = 16.
False
T/F: If you have a score of X = 76 on an exam with m = 70, you should expect a better grade if s = 10 than if s = 5.
False
T/F: In a population with a mean of m = 40 and a standard deviation of s = 8, a score of X = 46 would be an extreme value, far out in the tail of the distribution.
False
T/F: Multiplying every score in a sample by 3 will not change the value of the standard deviation.
False
Q: For the following scores, which of the following actions will increase the range? Scores: 3, 7, 10, 15
Subtract 3 points from the score X = 3
Q: Which of the following actions will have no effect on the value of the standard deviation?
Subtract 5 points from every score in the distribution
T/F: 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
T/F: For a population of N = 4 scores with SX = 10 and SX2 = 30, SS = 5.
True
T/F: If the scores in a population range from a low of X = 5 to a high of X = 14, then the population standard deviation must be less than 10 points.
True
T/F: If you have a score of X = 66 on an exam with m = 70, you should expect a better grade if s = 10 than if s = 5.
True
T/F: It is easier to see the mean difference between two samples if the sample variances are small.
True
T/F: The range is usually considered to be a relatively crude measure of variability.
True
T/F: The value for SS can never be less than zero.
True
T/F: To calculate the variance for a population, SS is divided by N.
True
Q: Under what circumstances is the computational formula preferred over the definitional formula when computing SS, the sum of the squared deviations, for a sample?
When the sample mean is not a whole number
Q: Under what circumstances would a score that is 10 points below the mean be considered to be an extreme value?
When the standard deviation is much less than 10
Q: A population of scores has m = 50 and s = 5. If every score in the population is multiplied by 3, then what are the new values for the mean and standard deviation?
m = 150 and s = 15
Q: Which of the following symbols identifies the population standard deviation?
s (italicized)
Q: On an exam with a mean of m = 70, you have a score of X = 75. Which of the following values for the standard deviation would give you the highest position within the class?
s = 1
Q: On an exam with a mean of m = 70, you have a score of X = 65. Which of the following values for the standard deviation would give you the highest position within the class?
s = 10
Q: A set of 10 scores has SS = 90. If the scores are a sample, the sample variance is ____, and if the scores are a population, the population variance is ____.
s2 = 10; s2 = 9
Q: A sample of n = 9 scores has a variance of s2 = 18. If the scores were a population, what value would be obtained for the population variance.
s2 = 16
Q: There is a 6-point difference between two sample means. If the two samples have the same variance, which of the following values would make the mean difference easiest to see in a graph showing the two distributions?
s2 = 2
Q: For 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?
s=1
Q: For a particular population, 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