STAT 226
Homework 2 Solution
Total points:
120
Problem 1.
(a)
FALSE
(ErrorAny curve)—Correct
Æ
Any curve that approximates a histogram
and
has an area of one under it
is a density curve. [Note: We can adjust the scale(s)
of the histogram so that an approximate curve can become a density curve. See
text example 1.15 (with figures) of page 5253. JMP automatically gives a density
curve under
fit distribution
Æ
smooth curve
.]
(b)
FALSE
(Errorany)—Correct
Æ
Mean and median of
symmetric
distributions are
always equal.
(c)
FALSE
(Errorany distribution)—Correct
Æ
The 68–95–99.7 Rule applies to normal
distributions only.
(d)
FALSE
Correct
Æ
The standard deviation of a set of observations is only equal to zero,
when all observations are of the same value.
(e)
TRUE
(f)
TRUE
(g)
FALSE
(Error larger the zscore)—Correct
Æ
The
smaller the absolute value of
the
zscore
of an observation the closer this observation is to the mean of the
distribution. (
Note: there are other ways to correct/write this)
(h)
FALSE
(Error—mean)—correct
Æ
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
standard deviation
.
F
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.
 Fall '08
 ABBEY
 Normal Distribution, Standard Deviation, normal quantile plot

Click to edit the document details