chapter 4 variability

what is the range for the following scores? 5, 7, 9, 15

10 or 11 points

for the following scores, find the interquartile range 3, 4, 4, 1, 7, 3, 2, 6, 4, 2 1, 6, 3, 4, 5, 2, 5, 4, 3, 4

2

what is the standard deviation for the following population of scores? 1, 3, 9, 3

3

what is the variance for the following sample of n=5 scores? scores: 2, 0, 8, 2, 3

36/4 = 9

what is the SS, the sun of the squared deviations, for the following population of N = 5 scores? 1, 9, 0, 2, 3

50

what is the variance set of the following set of scores? 4, 1, 7

6

a population of N = 8 scores has a standard deviation of σ = 3. what has the value of SS for the population?

72

which of the following sets of scores has the largest variance?

1, 3, 8, 12

a set of scores ranges from a high of X = 25 to a low of X = 12 and had a mean of 17. which of the following is the most likely value for the standard deviation for these scores?

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 the sample means, what value will be obtained?

30

for the following scores, which of the following actions will increase the range? 3, 7, 10, 15

add 4 points to the score X = 15

which of the following explains why it is necessary to make a correction to the formula for sample variance?

if the sample variance is computed by dividing by n instead of n - 1, the resulting values will tend to underestimate the population variance

which of the following is a consequence of increasing variability?

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

under what circumstances if the computational formula preferred over the definitional formula when computing SS, the sun of the squared deviations, for a sample?

when the sample is not a whole number