Question

Scores on a test have a mean of 66 and Q3 is 80. The scores have a distribution that is approximately normal. Find the standard deviation. Round your answer to the nearest tenth. Group of answer choices 10.5 20.9 18.7 9.4

Answer #1

Solution:-

Given that,

mean = = 66

x = 80

The z dist'n Third quartile is,

P(Z < z) = 75%

= P(Z < z) = 0.75

= P(Z < 0.67 ) = 0.75

z = 0.67

Using z-score formula,

x = z * +

80 = 0.67 * + 66

= 80 - 66 / 0.67

= 20.9

Scores on a test have a mean of 72.9 and 9 percent of the scores
are above 85. The scores have a distribution that is approximately
normal. Find the standard deviation. Round your answer to the
nearest tenth, if necessary.

Scores on a test have a mean of 71 and Q3 is 82. The scores have
a distribution that is approximately normal. Find P90

The distribution of math test scores on a standardized test
administered to Texas tenth-graders is approximately Normal with a
mean of 615 and a standard deviation of 46. Below what score do the
worst 2.5% of the scores fall? (Hint: apply the 68-95-99.7 Rule.)
Round your answer to the nearest integer.

The distribution of scores on a standardized aptitude test is
approximately normal with a mean of 500 and a standard deviation of
95 What is the minimum score needed to be in the top 20%
on this test? Carry your intermediate computations to at least
four decimal places, and round your answer to the nearest
integer.

1.
Scores on an aptitude test form a normal distribution
with a mean of 140 and a standard deviaition of 12. Find the
percent that score between 131 and 155.
Group of answer choices
12.10%
22.66%
32.44%
66.78%
10.56%
2.
The scores of students on a standardized test form a
normal distribution with a mean of 140 and a standard deviaition of
12. If 36000 students took the test, how many scored above
149?
Group of answer choices
9634
7922...

Assume that a set of test scores is normally distributed with a
mean of 80 and a standard deviation of 20. Use the 68-95-99.7 rule
to find the following quantities.
The percentage of scores less than 80 is __%
The percentage of scores greater than 100 is _%
The percentage of scores between 40 and 100 is _%
Round to the nearest one decimal

Scores on an aptitude
test have been observed to be approximately normal with a mean of
76and a standard deviation of 5.
If 1000 people took
the test, how many would you expect to score above 80?

1) Mathematics achievement test scores for 500 students were
found to have a mean and a variance equal to 590 and 4900,
respectively. If the distribution of test scores was mound-shaped,
approximately how many of the scores would fall into the interval
520 to 660? (Round your answer to the nearest whole number.)
2) Approximately how many scores would be expected to fall into
the interval 450 to 730? (Round your answer to the nearest whole
number.)

test scores in a MATH 1030 class is approximately normally
distributed with mean 86 and standard deviation 6. Round answers to
the nearest tenth of a percent. a) What percentage of scores will
be less than 88? % b) What percentage of scores will be more than
82? % c) What percentage of scores will be between 81 and 87? %

Assume that a set of test scores is normally distributed with a
mean of 80 and a standard deviation of 25. Use the 68-95-99.7 rule
to find the following quantities.
c. The percentage of scores between 30 and 105 is %.?
(Round to one decimal place as needed.)

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