STATS 212 - CHAPTER 4 LEARNING CHECKS
which of the following sets of scores has the largest variance? 1, 3, 8, 12 12, 13, 14, 15 2, 2, 2, 2 22, 24, 25, 27
1, 3, 8, 12
what is the range for the following set of scores? scores: 5, 7, 9, 15 4 POINTS 5 POINTS 10 OR 11 POINTS 15 POINTS
10 or 11 points
what is the standard deviation for the following population of scores? scores: 1, 3, 9, 3 36 9 6 3
3
a set of scores ranges from a high of X = 24 to a low of X = 12 ad has a mean of 18. which of the following is the most likely value for the standard deviation for these scores? 3 POINTS 6 POINTS 12 POINTS 24 POINTS
3 points
all the possible samples of n = 3 scores are selected from a population with μ = 30 and σ = 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 GREATER THAN 30 LESS THAN 30 NEAR 30 BUT NOT EXACTLY EQUAL TO 30
30
what's the variance for the following sample of n = 5 scores? scores: 2, 0, 8, 2, 3 81/4 = 20.25 36/4 = 9 36/5 = 7.2 sqrt 9 = 3
36/4 = 9
what is SS, the sum of the squared deviations, for the following population of N = 5 scores? scores: 1, 9, 0, 2, 3 10 41 50 95
50
what is the variance for the following set of sores? scores: 4, 1, 7 66/3 = 22 18 9 6
6
a population of N = 8 scores has a standard deviation of σ = 3. what is the value of SS, the sum of the squared deviations, for this population? 72 24 8 sqrt 3 9/8 = 1.125
72
which of the following is a consequence of increasing variability? A. THE DISTANCE FROM ONE SCORE TO ANOTHER TENDS TO INCREASE AND A SINGLE SCORE TENDS TO PROVIDE A MORE ACCURATE REPRESENTATION OF THE ENTIRE DISTRIBUTION B. THE DISTANCE FROM ONE SCORE TO ANOTHER TENDS TO INCREASE AND A SINGLE SCORE TENDS TO PROVIDE A LESS ACCURATE REPRESENTATION OF THE ENTIRE DISTRIBUTION C. THE DISTANCE FROM ONE SCORE TO ANOTHER TENDS TO DECREASE AND A SINGLE SCORE TENDS TO PROVIDE A MORE ACCURATE REPRESENTATION OF THE ENTIRE DISTRIBUTION D. THE DISTANCE FROM ONE SCORE TO ANOTHER TENDS TO DECREASE AND A SINGLE SCORE TENDS TO PROVIDE A LESS ACCURATE REPRESENTATION OF THE ENTIRE DISTRIBUTION
B. the distance from one score to another tends to increase and a single score tends to provide a less accurate representation of the entire distribution
a research study obtains a mean of 12.7 and a standard deviation of 2.3 for a sample of n = 25 participants. how would the sample mean and standard deviation be reported in a research journal report? M = 12.7 AND s = 2.3 M = 12.7 AND SD = 2.3 Mn = 12.7 AND s = 2.3 Mn = 12.7 AND SD = 2.3
M = 12.7 and SD = 2.3
one sample os selected to represent scores in treatment 1 and a second sample is used to represent scores is treatment 2. which set of sample statistics would present the clearest picture of a real mean difference between the two treatments? M1 = 40, M2 = 45, AND BOTH VARIANCES = 15 M1 = 40, M2 = 45, AND BOTH VARIANCES = 3 M1 = 40, M2 = 42, AND BOTH VARIANCES = 15 M1 = 40, M2 = 42, AND BOTH VARIANCES = 3
M1 = 40, M2 = 45, and both variances = 3
for the following scores, which of the following actions will increase the range? scores: 3, 7, 10, 15 ADD 4 POINTS TO THE SCORE X = 3 ADD 4 POINTS TO THE SCORE X = 7 ADD 4 POINTS TO THE SCORE X = 10 ADD 4 POINTS TO THE SCORE X = 15
add 4 points to the score x = 15
a researcher takes all of the possible samples of n = 4 form a population. next, the researcher computes a statistic for each sample and calculates the average of all the statistics. which of the following statements is most accurate? A. IF THE AVERAGE STATISTIC OVERESTIMATES THE CORRESPONDING POPULATION PARAMETER, THEN THE STATISTIC IS BIASED B. IF THE AVERAGE STATISTIC UNDERESTIMATES THE CORRESPONDING POPULATION C. IF THE AVERAGE STATISTIC IS EQUAL TO THE CORRESPONDING POPULATION PARAMETER, THEN THE STATISTIC IS UNBIASED D. ALL OF THE ABOVE
all of the above
T/F: a biased statistic has been influenced by researcher error
false
T/F: if all the scores in a data set are the same, the standard deviation is equal to 1.00
false
T/F: the computational and definitional formulas for SS sometimes give different results
false
T/F: the standard deviation is the distance from the mean to the farthest point on the distribution curve
false
a researcher takes a sample from a population and computes a statistic for the sample. which of the following statements is correct? A. IF THE SAMPLE STATISTIC OVERESTIMATES THE CORRESPONDING POPULATION PARAMETER, THEN THE STATISTIC IS BIASED B. IF THE SAMPLE STATISTIC UNDERESTIMATES THE CORRESPONDING POPULATION PARAMETER, THEN THE STATISTIC IS BIASED C. IF THE SAMPLE STATISTIC IS EQUAL TO THE CORRESPONDING POPULATION PARAMETER, THEN THE STATISTIC IS UNBIASED D. NONE OF THE ABOVE
none of the above
the standard deviation measures... SUM OF SQUARED DEVIATION SCORES STANDARD DISTANCE OF A SCORE FROM THE MEAN AVERAGE DEVIATION OF A SCORE FROM THE MEAN AVERAGE SQUARED DISTANCE OF A SCORE FROM THE MEAN
standard distance of a score from the mean
a sample of four scores has SS = 24. what's the variance? THE VARIANCE IS 6 THE VARIANCE IS 7 THE VARIANCE IS 8 THE VARIANCE IS 12
the variance is 8
T/F: a sample systematically has less variability than a population
true
T/F: on average, an unbiased sample statistic has the same value as the population parameter
true
under what circumstances is the computational formula preferred over the definitional formula when computing SS for a sample? WHEN THE SAMPLE MEAN IS A WHOLE NUMBER WHEN THE SAMPLE MEAN IS NOT A WHOLE NUMBER WHEN THE SAMPLE VARIANCE IS A WHOLE NUMBER WHEN THE SAMPLE VARIANCE IS NOT A WHOLE NUMBER
when the sample mean is not a whole number
for which of the following distributions would X = 35 be an extreme score? μ = 30 AND σ = 5 μ = 30 AND σ = 10 μ = 25 AND σ = 5 μ = 25 AND σ = 10
μ = 25 and σ = 5
if 5 points are added to every score in a population with a mean of μ = 45 and a standard deviation of σ = 6, what are the new values for μ and σ? μ = 45 AND σ = 6 μ = 45 AND σ = 11 μ = 50 AND σ = 6 μ = 50 AND σ = 11
μ = 50 and σ = 6
a population of μ = 6 and σ = 2. each score is multiplied by 10. what is the shape of the resulting distribution? μ = 60 AND σ = 2 μ = 6 AND σ = 20 μ = 60 AND σ = 20 μ = 6 AND σ = 5
μ = 60 AND σ = 20