This preview shows pages 1–2. Sign up to view the full content.
Econ 310: Problem Set #6 Solutions
Andres AradillasLopez
1. Exercise 4.52.
(a) Curve on the below. A good procedure is to draw the curve ﬂrst,
locate the points where the curvature changes, then mark the hori
zontal axis. Students may at ﬂrst make mistakes like drawing a half
circle instead of the correct "bellshaped" curve or being careless about
locating the standard deviation. (b) About 0.017:
P
(
Y >
300) =
P
±
Y
¡
266
16
>
300
¡
266
16
¶
=
P
(
Z >
2
:
125). Software gives 0.0168; Table
A gives 0.0166 for
¡
2
:
13 and 0.0170 for
¡
2
:
12 (so the average is again
0.0168).
2. Exercise 4.60.
Let "S" mean that a student supports funding and "O" mean that
the student opposes funding. (a)
P
(
SSO
) = (0
:
6)(0
:
6)(0
:
4) = 0
:
144.
(b) See the top two lines of the table below. (c) The distribution is
given in the bottom two lines of the table. For example,
P
(
X
= 0) =
(0
:
6)(0
:
6)(0
:
6) = 0
:
216, and in the same way,
P
(
X
= 3) = 0
:
4
3
=
0
:
064. For
P
(
X
= 1), note that each of the three arrangements that
give
X
= 1 have probability 0.0144, so
P
(
X
= 1) = 3(0
:
144) = 0
:
432.
Similarly,
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
 Rush

Click to edit the document details