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15 questions
What is the formula to find the z-score for population?
$z=x-\mu$
$z=\frac{\sigma-\mu}{x}$
$z=\frac{\sigma}{\sqrt{n}}$
$z=\frac{x-\mu}{\sigma}$
Which of the following is a formula that describes calculating a z-score?
Z = (score - mean) / stand. devation
Z = (mean - score) / stand. dev.
Z = score/stand. dev/ mean
Z = dragonball
What is the purpose of z-scores?
to describe the exact location of a score within a distribution
to find the mean of the distribution
to describe the shape of the distribution
to find the standard deviation of the distribution
The sign of the z-score indicates whether the location is above(positive) or below(negative) the mean.
True
False
Find the Z-score.
Mean = 22
Standard Deviation: 3.1
x = 29
2.26
16.45
-2.26
1.26
Adam's Z-score on a test is +2.50. What does this mean?
Adam's score has a 2.5% chance of being better than any other randomly selected score.
Adam's test score was better than 25% of his peers.
He scored 2.5 standard deviations above the average.
He did terrible.
What is the Z-score for Paula if she got 1400 on the SAT, the mean was 1100 and the standard deviation was 275?
-1.90
-1.09
+1.09
+1.90
Find the mean.
Z-score = -1.4
Standard Deviation: 7
x = 20
29.8
10.2
-21
35
If I tell you that you scored at the 55th percentile on your final exam, you would know:
55% of the class scored the same or worse than you did
You earned a 55% on the exam
You failed the exam
45% of the class scored worse than you did
In a factory, the weight of the concrete poured into a mold by a machine follows a normal distribution with a mean of 1150 pounds and a standard deviation of 22 pounds. What weight falls at the 50th percentile?
1106 pounds
1128 pounds
1150 pounds
1172 pounds
Scores on a certain standardized test have a mean of 500, and a standard deviation of 100. What score would you need to fall at the 84th percentile?
84
400
500
600
Jeremy scored a 74 on his test. 16 of the 26 scores on the test are less than or equal to 74. What is Jeremy's percentile rank?
62nd percentile
38th percentile
74th percentile
26th percentile
Shannon spent $60 on her homecoming dress. If 197 of the 300 students that bought a homecoming dress spent more than Shannon, what is the percentile rank of her cost?
103rd percentile
34th percentile
66th percentile
20th percentile
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