Question

the average mark (in percentage) in statistics test for a class comprising 300 students is 54%. if the marks are normally distributed with a standard deviation of 8%, the number of students with a mark of over 70% is

Answer #1

The marks in a Business Statistics class are normally
distributed with a mean of 65% and a standard deviation of 12%.
What percentage of the class received a mark of 90% or higher?

7) Students in first-year statistics wrote a 100 point test
where the grades were normally distributed. The mean was 60 and the
standard deviation was 12. Students in first-year calculus also
wrote a 100 point test where the grades were normally distributed.
The mean was 68 and the standard deviation was 8.
A. Brianna has a mark of 81 in statistics and a mark of 83 in
calculus. Which mark is “better” compared to her classmates?
B. The statistics professor...

If test marks are assumed to be normally distributed and 70% of
the students scored greater than a mark of 60(out of 100), and 10%
scored over 90, determine the mean and standard deviation of the
test marks.

The time it takes for a statistics professor to mark a single
midterm test is normally distributed with a mean of 4.9 minutes and
a standard deviation of 1.7 minutes. There are 57 students in the
professor's class. What is the probability that he needs more than
5 hours to mark all of the midterm tests?

Scores of students in a large Statistics class test are normally
distributed with a mean of 75 points and a standard deviation of 5
points.Find the probability that a student scores more than 80
pointsIf 100 students are picked at random, how many do you expect
to score below 70 points?If top 10% of students obtain an A grade,
how much should a student obtain to get an A grade.Suppose four
students are picked at random, find the probability that...

A student wants to estimate the average mark on a statistics
test to within 5 marks (out of 100), with 95% confidence. A
preliminary sample yielded a standard deviation of 15.54. How big a
sample size is necessary? Round to the nearest whole number.

Q2. A set of final test marks in an introductory
statistics unit is normally distributed with a mean of 73 and a
standard deviation of 8.
If the lecturer gives grades of High Distinction to the top 5%
of students on tests described above (i.e. mean of 73 and a
standard deviation of 8), are you better off with a mark
of 80 on this test or a mark of 68 on a different test where the
mean is 62...

The marks of students taking a statistics examination is
normally distributed with a standard deviation of 10 marks. 10% of
students scored above 85 marks for the examination. Determine the
percentage of students who scored above 65 marks for the
examination.

Suppose that the class marks on your last history test were
normally distributed with a mean grade of 70 points and a standard
deviation of 8 points. Using table Z answer the questions below.
Show your work where requested.
1. What percentage of students got grades less than 50? Show
your work.
2. What percentage of students got grades more than 50?
3. What percentage of students are more than 1.5 standard
deviations from the mean?
4. What percentage of...

The average on a statistics test was 75 with a standard
deviation of 11. If the test scores are normally distributed, find
the probability that the mean score of 36 randomly selected
students is between 72 and 81.

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