There are 2 pages in this exam:
Page: 1 2
1. Question:
(TCO 6) In the standard normal distribution, the standard deviation is always
Your Answer:
0
1
( Ch 5: By definition, the standard deviation = 1. )
CORRECT
2
none of these
Points Received: 5 of 5
2. Question:
(TCO 6) The area under the standard normal curve is
Your Answer:
0
1 ( Ch 5: The total area under ANY normal probability distribution is always 1. )
CORRECT
2
none of these
Points Received: 5 of 5
3. Question:
(TCO 6) If Mary gets a 90 on a physics test where the mean is 85 and the standard deviation is 4.59,
where does she stand in relation to her classmates?
Your Answer:
She is in the top 15%. ( Ch 5: z = (90 – 85)/4.59 = 1.09. Area to the left is 0.8621. Thus
86.21% of test scores are below 90. ) CORRECT ANSWER
She is in the bottom 15%. INCORRECT
She is in the top 5%.
She is in the bottom 5%.
Points Received: 2 of 5
Comments:
z = (90 – 85)/4.59 = 1.09. Area to the left is 0.8621. Thus 86.21% of test scores are below 90.)
4. Question:
(TCO 6) In a normal distribution with mu = 25 and sigma = 6, what number corresponds to z = 3?
Your Answer:
40
43
( Ch 5: x = mu + z * sigma, so x = 43 )
CORRECT
46
none of these
Points Received: 5 of 5
5. Question:
(TCO 6) Let’s assume you have taken 100 samples of size 64 each from a normally distributed
population. Calculate the standard deviation of the sample means if the population’s variance is 49.
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 Fall '10
 Mereck
 Math, Statistics, Normal Distribution, Standard Deviation, mean annual income

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