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STAT 1000 Assignment 3
DUE:
February 29th (Wed. Eve. Section), March 1st (T/Th. Sections),
March 2nd (MWF. Sections)
SHOW ALL YOUR WORK
1.
[4]
A variable
X
has a distribution which is described by the density curve shown below:
(a) What proportion of observations of
X
are less than 5?
(b) What proportion of observations are between 2 and 4?
2.
[2]
A random variable
X
has a triangular distribution on the interval 5 to 10. What must
the height be in order for this to be a true density curve?
3.
[1]
A telemarketing ﬁrm in a certain city uses a device that dials residential telephone
numbers in that city at random. Of the ﬁrst 100 numbers dialed,
51%
are unlisted.
This is not surprising because
48%
of all residential phone numbers in this city are
unlisted. Explain whether the percentages in
bold
are either a statistic or parameter.
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View Full Document 4.
[11]
Let
Z
follow a standard normal distribution, ﬁnd the following proportions:
(a)
P
(
Z <
0
.
50)
(b)
P
(
Z >

1
.
25)
(c)
P
(
Z >
2
.
69)
(d)
P
(
Z <

3
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This note was uploaded on 04/01/2012 for the course STAT 1000 taught by Professor Xu during the Spring '12 term at Manitoba.
 Spring '12
 XU

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