This preview shows pages 1–2. Sign up to view the full content.
Homework 2
Due Thursday, February 14
th
in Class
SHOW
ALL
YOUR
WORK
FOR FULL CREDIT!
PRINT
AND
TURN
IN JMP OUTPUT AS INDICATED!
For general homework rules, read the Homework Guidelines that can be found on the course web
page for all Stat 226 sections (see address below) following the link Homework.
http://www.stat.iastate.edu/courses/stat226/homework.htm
You will need to download the following file (from the Homework section of the stat 226
webpage):
IsItNormal.JMP.
Problem 1.
For each of the following problems, write TRUE if the statement is true as stated, or FALSE if it
is untrue. If false, indicate the error in the statement and change it so that the statement becomes
correct. Make sure to read each question carefully!
(a)
Any curve that approximates the overall shape of a histogram is a density curve.
(b)
The mean and the median of any distribution are always equal.
(c)
The 68–95–99.7 Rule can be applied to any distribution, not just normal
distributions.
(d)
The standard deviation is zero when the number of observations that are larger
than the mean equals the number of observations that are smaller than the mean.
(e)
A normal distribution is completely characterized by its mean and standard
deviation.
(f)
To compare data points from two different normal distributions one needs to find
and to compare their zscores.
(g)
The larger the zscore of an observation the closer this observation is to the mean
of the distribution.
(h)
According to the 68–95–99.7 Rule, the range of a data set coming from a Normal
distribution is approximately equal to six times the mean.
Problem 2.
Answer the following questions using Table A of the text. For each question sketch the standard
normal density curve and shade the corresponding area of interest in addition to finding the
actual proportion.
a)
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview. Sign up
to
access the rest of the document.
 Spring '08
 ABBEY
 Statistics

Click to edit the document details