Chapter 4 Stat Test
Which response option below is the standard deviation of the sample of n= 11 scores depicted below? a.s=2.61 b.s= 2.49 c.s=4 d.s=1.91
A
In a population of N= 10 scores obtained from a discrete variable for which 0 is not a possible score, the smallest score is X=8 and the largest is X= 20. What is the range for this population? a.10 b.20 c.8 d.12
D.12
Mr.Johnson has collected data from 100 people assessing their attitudes toward a recent referendum. He has calculated EX^2= 470 and (EX)= 150. Calculate the estimated population standard deviation for his data.
Estimated population standard deviation: 1.57
A group of 10 students participated in a study of nutritional awareness. What is the sample standard deviation of their scores? ( Deviation Method) 20, 19, 22, 20, 15,18, 15, 21, 19, 20 Sample Standard Deviation _________ Median ___________
Sample Standard Deviation: 2.33 Median: 19.5
A group 37. For the following data set, find the estimated population variance and the population standard deviation. ( computational/ raw score method) score. f 9 2 8 4 7 8 6 6 5 4 4 3 3 2 Variance_______ Standard Deviation________
Variance 2.58 Standard Deviation 1.61
One sample is selected to represent scores in treatment 1 and a second sample is used to represent scores in treatment 2. Which set sample of statistics would present the clearest picture of a real difference between the two treatments? a. M1= 36, M2=40, and both variances =6 b.M1= 38, M2=40, and both variances =43 c.M1= 36, M2=40, and both variances =43 d.M1= 38, M2=40, and both variances =6
a. M1= 36, M2=40, and both variances =6
Whats the variance for the following sample of n= 3 scores? Scores: 1,4,7 a. 9 b. 15 c. 6 d. 3
a.9
A sample of n=9 scores has SS=72. The variance for this sample is s^2=9. a.true b.false
a.true
What is the value of SS ( sum of squared deviations) for the following sample? Scores: 2,4,5,9 a. 10 b.26 c.16 d.5
b. 26
The symbol for sample variance is S a.True b. False
b. False
After a researcher adds 6 point to every score in a sample, the standard deviation is found to be s= 12. The original sample had a standard deviation of s=6. a. true b. false
b. false
If a population variance is 6, then the population standard deviation is σ=36. a.true b.false
b. false
The value for SS can be less than zero
b. false
In a sample with a mean of M= 4 made up of four scores, two scores are free to vary and the third and fourth scores are fixed. a. true b. false
b.false
Compute the interquartile range for the following scores that represent a continuous variable: 1,2,2,2,4,5,10,12 a.11 b.4.5 c.5.5 d.2
c. 5.5
( picture in messages) The box plot below depicts the median number of hours a population of N= 12 students reported studying for their first exam within a class. Which statement below is not true based on the box plot? a. the median is 5 b. the highest score in the distribution is 7 c. the interquartile range is 5 d. the lowest score in the distribution is 1
c. the interquartile range is 5
A population of scores has u= 10 and o= 2. If every score in the population is multiplied by 4 , then what are the new values from the mean and standard deviation? a. u= 10 and σ=8 b. u= 10 and σ=2 c. u= 40 and σ=8 d. u= 40 and σ=2
c. u= 40 and o=8
A sample of n= 6 scores has SS=40. If these same scores were a population, then the SS for the population would be _______. a. less than 40 b. This is impossible to determine without additional information c. 40 d. greater than 40
c.40
A population has SS= 100 and σ^2 =4. What is the value of E( X-u) for the population? a. 100 d.0 c.400 d.25
d. 25
What is the range for the following set of scores obtained for a discrete variable for which 0 is not a possible score? Score: 5,7, 9, 13 a.5 points b. 13 points c. 4 points d. 8 points
d. 8 points
Which of the following is NOT a unique advantage of the interquartile range as measure of variability? a. The interquartile range can be used for data measures with an ordinal scale of measurement. b. The interquartile range is less influenced than the range by extreme scores c. The interquartile range can be utilized in open-ended distributions. d. The interquartile range can be used for data measures with a ratio scale of measurement
d. The interquartile range can be used for data measures with a ratio scale of measurement
The sum of the squared deviation scores is SS= 20 for a sample of n=6 scores. What is the variance for this sample? a. s^2=5 b. s^2=100 c. s^2=80 d. s^2=4
d. s^2=4
For the following scores, which action will increase the range? scores: 2,6,11,15 a. subtract 4 points from the score X=11 b.subtract 3 points from the score X=15 c.subtract 3 points from the score X=6 d. subtract 1 points from the score X=2
d. subtract 1 points from the score X=2
Because Sample Variance are computed by dividing SS by n-1, the average value of the sample variances from all possible random samples consistently_______ the population variance. a. impossible to determine b. overestimate c. underestimate d. equal
d.equal
For a population of scores, the sum of the deviation score is equal to 0. a. true b. false
a. True
Why do deviation scores have to be squared before calculation the standard deviation? a. if deviation scores are not squared, then the average distance from the mean will always equal 0 b. Squaring deviation scores allows for degrees of freedom to be calculated C. squaring is necessary when calculating inferential statistics d. if deviation scores are not squared, then the interquartile ranges are incalculable
a. if deviation scores are not squared, then the average distance from the mean will always equal 0
Which Symbol below identifies the sample variance? a. s^2 b. σ c.σ^2 d.s
a. s^2
A sample with a variance of s^2=36 has a standard deviation equal to s=6 a.true b.false
a. true
Data sets can be divided into four quartiles. a. true b. false
a. true
A population of N= 10 scores has μ= 21 and σ=3. What is the population variance? a.2 b.100 c.7 d.9
d.9
For a sample with M=10 and s=2, a score of X=13, would be considered an extreme score, far out in the tail of the distribution. a. true b. false
a. true
If a person scores X= 80 on an exam with m=75, they scores wore relative to others in the class if σ=8 than if σ=4. a. true b. false
a. true
Multiplying every score in a sample by a constant value will change the value of the standard deviation. a.true b. false
a. true
The range is considered to be a relatively crude measure of variability a. true b. false
a. true
The sample variance and sample standard deviation is also referred to as the estimated population variance and estimated population standard deviation, respectively a. true b. false
a. true
To calculate the variance for a sample, SS is divided by the appropriate degrees of freedom a. true b.false
a. true
If sample variance were to be computed by dividing SS by n, then the average value of the sample variances from all the possible random samples would consistently ______ the population variance. a. underestimate b. equal c. overestimate d. impossible to determine
a. underestimate
A population of N= 5 scores has a mean of u=20 and a standard deviation of σ=4. Which of the following is the correct interpretation of the standard deviation? a. the average distance of score from the mean of u=20 is 5 points b. the average squared distance of scores from the mean of u=20 is points c. the average distance of scores from the mean of u=20 points is 4 points d. the average distance of score from the mean of u=20 is 1 point
C.the average distance of scores from the mean of u=20 points is 4 points