PTK Quiz questions and answers
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Suppose a student received a raw score of 41 which corresponded to the 67th percentile. What
does this information mean to the teacher? ✔✔67% of the students who took this
...
PTK Quiz questions and answers
already passed
Suppose a student received a raw score of 41 which corresponded to the 67th percentile. What
does this information mean to the teacher? ✔✔67% of the students who took this same exam
earned a raw score of 41 or less.
A percentile is ✔✔the value or score on the ordered array of data that indicates the percentage of
the scores that fall at or below that value. The third quartile establishes the point where 75% of
the score are below it. Therefore, at the 67th percentile, this student did not score above the third
quartile.
Which of the following measures of central tendency is MOST strongly influenced by extreme
scores? ✔✔The correct answer is A. The mean is most greatly influenced by extreme scores.
Given a normal distribution of student scores, what percentage of the scores will fall within two
standard deviations of the mean? ✔✔95% of the data points will fall between two standard
deviations of the mean. 68%, shows the percentage of data points that will fall within one
standard deviation of the mean. Choice A is incorrect because the standard deviation includes the
area on both sides of the mean.
Which of the following BEST describes what a Pearson coefficient of zero between scores on
two tests would indicate to a teacher?
The scores on the two tests are ... ✔✔A Pearson coefficient of zero indicates that the scores on
the two tests are not related in a reliable or predictable way.
Which of the following assessments would be MOST likely to produce a normal curve when
graphing the results? ✔✔State-wide achievement exam The correct answer is D. The normal
curve is most likely to apply to a large, statistically "normal" population.
If the graph of a data distribution shows that the mean is graphed to the right of the mode, which
of the following is most likely true? ✔✔The results are positively skewed. In a positively skewed
frequency distribution, the mean moves to the right of the mode and the majority of the scores
fall below the mean. For a frequency distribution that is negatively skewed, the mean moves to
the left of the mode and is shaped so that the majority of its scores fall above its mean. In a
positively skewed distribution, the median is generally less than the mean.
What would a large standard deviation most likely indicate to a teacher? ✔✔The scores are
widespread. A large standard deviation means an excessive spread of data well dispersed away
from the mean. A small standard deviation indicates a tight cluster of data points near the mean.
Given a data set with a small range, which of the following would be the BEST measure of
central tendency? ✔✔The mean is considered the best measure of central tendency, unless
exaggerated by extreme scores.
Which of the following BEST describes a graph of a bimodal distribution? ✔✔"Bimodal" means
that there are two modes or peaks within the same distribution of data. The two modes will not
necessary reflect two extremes and may be clustered near one another.
What is the numeric difference between the mode and the median of the following set of scores?
Student Score 25 25 45 60 60 75 75 75 80 ✔✔15; The mode (most frequently occurring score) is
75 and the median (which divides a distribution exactly in half) is 60. 75 − 60 = 15.
What is the unbiased standard deviation of the following sample?
Student Score 1 3 5 7 9 ✔✔3.16; Step 1: The mean is 5.
Step 2: Subtracting the mean from each score.
(1−5) = −4
(3−5) = −2
(5−5) = 0
(7−5) = 2
(9−5) = 4
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