Module 3 Flashcards
A measure of variability provides information about A) The level of performance B) Shape of the distribution C) Individual differences D) Kurtosis
C) Individual differences
If the lowest score is 51 and the highest score is 92, the range is A) 41 B) 41.1 C) 41.5 D) 42
A) 41
Eliminating some scores from a point near the mean will
A) Increase the standard deviation
B) Not affect the standard deviation
C) Decrease the standard deviation
D) Affect the standard deviation in an unpredictable way
A) Increase the standard deviation
Consider the two scores, 4 and 8. SS = A) 8 B) 4 C) 0 D) cannot be determined without further information
A) 8
SS/n is A) The average deviation B) The standard deviation C) The variance D) None of the above
The variance
Which among the following groups of scores would show the least variability when measured by the standard deviation? (no computations necessary) A) 1 4 5 6 9 B) 1 2 5 8 9 C) 61 65 65 65 69 D) 61 63 65 67 69
C) 61 65 65 65 69
The mean score on a quiz is 7, and the standard deviation is 0. This shows that A) A calculation error has been made B) The distribution is normal C) The distribution is rectangular D) All persons scored 7 on the quiz
D) All persons scored 7 on the quiz
Computing the standard deviation directly from deviation scores is useful:
A) For understanding the nature of s
B) When the score have not yet been grouped into a frequency distribution
C) When n is large
D) When the original scores are whole numbers
A) For understanding the nature of s.
For the two scores, 2 and 4, (∑X)² is A) 2 B) 6 C) 20 D) 36
D) 36
∑X² - (∑X)² / n is one formula for A) s² B) s C) ∑(X -X)² D) SS
D) SS
At one stage of calculation, we have S = √(-36) . From this, we know
A) S=6
B) One or more scores must have been wrongly copied from the original set
C) We have made an error in computation
D) Either (B) or (C) has occurred
C) We have made an error in computation
Which measure is not dependent on the value of each score? A) Standard deviation B) Variance C) Range D) None of the above
C) Range
The properties of the standard deviation are most closely related to those of the A) Mean B) Median C) Mode D) Median and mode
A) Mean
With larger sample size, we would expect which measure(s) also to be larger? A) Standard deviation B) Variance C) Range D) None of the above
C) Range
If one score in a distribution is changed to another value, it is certain that
A) The range has changed
B) The variance has changed
C) The standard deviation has changed
D) Both standard deviation and variance have changed
D) Both standard deviation and variance have changed
In a normal distribution, about 5% of the scores fall outside of the limits A) X ± 0.5S B) X ± 1S C) X ± 1.5S D) X ± 2S
D) X ± 2S
A frequency distribution of observations is approximately normal with x̄ = 60 and S = 5. The middle 95% of the cases will fall (approximately) between A) 45 and 75 B) 47.5 and 72.5 C) 50 and 70 D) 55 and 65
C) 50 and 70
A frequency distribution of scores is normal with a mean of 80 and a standard deviation of 9. Roughly \_\_\_\_\_\_ of the cases fall between scores of 71 and 89. A) Half B) Two thirds C) Almost all D) 95%
B Two thirds
In a normal distribution, we expect about what percent of scores to fall above a score three standard deviations below the mean (i.e., above x̄ - 3S) A) More than 99% B) 97.5% C) 95% D) 84%
A) More than 99%
If performance is normally distributed, and grades of A are given to those who score at 1 standard deviation above the mean or better, we should expect about what proportion of students to earn an A? A) 32% B) 16% C) 5% D) 2.5%
B) 16%
Given: n1 > n2 and s₁ > s₂. You therefore know that: A) x̄₁ > x̄₂ B) s(pooled) is closer to s₂ than s₁ C) S₁² > S₂² D) s(pooled) is closer to s₁ than s₂
D) s(pooled) is closer to s₁ than s₂
An effect size
A) Expresses the magnitude of a mean difference in standard deviation units
B) Is used for conveying peakedness of a distribution
C) Can be misinterpreted if the horizontal and vertical axes are not scaled comparably
D) Is large when a distribution is markedly skewed
A) Expresses the magnitude of a mean difference in standard deviation units
According to Cohen (1988), an effect size of -.85 would be considered A) Negligible B) Small C) Moderate D) Large
D) Large
Given:
n1 = 16, x̄1 = 35, S₁² = 16
n2 = 16, x̄2 = 27, S₂² = 16
S(pooled) = A) 2 B) 4 C) 16 D) cannot be computed from these data
B) 4
Given:
n1 = 16, x̄1 = 35, S₁² = 16
n2 = 16, x̄2 = 27, S₂² = 16
d = A) +0.50 B) +2 C) +8 D) +16
B) +2
Seniors at two universities take the Graduate Record Examination. Students from the first institution earn a mean of 520; those from the second, 505. The standard deviation of this test was 100. Would you say that seniors at the first institution seem to be
A) Much superior to those at the second
B) A little superior to those at the second
C) Different, but it’s hard to say without knowing the range
D) Normally distributed
B) A little superior to those at the second
