Instructions
There are three parts to this assignment. Each part will require
you to enter your answers into a document that you will submit to
the dropbox for this assignment.
Part 1:
The weights of all one hundred (100) 9th graders at a school are
measured, and it is found that the mean of all the measurements is
100 lbs., with a standard deviation of 15
lbs. Explain how you
would use this information to determine the percentage of students
who weighed between 85 lbs and 115 lbs. Make sure your explanation
includes the use of z-scores.
Part 2:
Using the example in part 1 above, answer the following
questions in the same document you used to answer the questions
from part 1. Make sure you show all the work required by the
questions.
What is the percentage of students who weighed between 85 lbs
and 115 lbs? (Show calculations)
What is the z-score of a student who weighed 105 lbs? (Show
calculations)
If a student weighed only 60 lbs, how many students out of the
one hundred 9th graders would weigh more? (Hint: calculate the
percentage 1st)
Part 3:
The following year, the 9th grade students are weighed again,
and this time it is found that the mean of all weights is 108 lbs,
and the standard deviation is 17 lbs. Answer the following
questions, using the same document you used in parts 1 and 2 to
show how you arrived at your answers.
Compare two students, one from the first class who weighed 98
lbs, and one from the second class who weighed 100 lbs.
Which of the two students was heavier relative to their class?
(Hint:compare z-scores)
What percentage of students in the first class were heavier than
the 98 lb. student?
What percentage of students in the second class were heavier
than the 100 lb. student?
