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