Solutions to Exam #1, Version C
Q
No.
on
Ver
A
Solutions
Version A
1
The problem states to find if cars performance is better than
manufacturers
rating , so Ha : M > 30 hence Ho:M<=30
E
2
Tcrit is printed in the output Table as 2.62
A
3
Since T* (2.04)< Tcrit(2.62)
we FTR
Ho; and conclude there is
insufficient evidence for alternate hypothesis to be true.
B
4
Xbar + T(alpha)(S/sqrt(n) =
31.853 + 2.62(3.5/3.87)=34.5
D
5
We chose T test because sample size is small and population std.
deviation is not known
B
6
The salesman
believes that cars get over 400 miles ,so
Ha: M >
400 and Ho: M<=400
B
7
T cal= (Xbar M)/(s/sqrt(n)) =4.01
D
8
Z value of
0.889 corresponds (is close to) to area of
0.3130, so p
value is 0.50.3130
=0.1870
E
9
Since Pvalue (0.187) > 0.1 we FTR Ho and conclude that there
is
insufficient evidence that the cars give over 400 miles.
D
10
Tcrit value from the output Table given is 1.3968
E
11
Calculated value of Test Statistic is 4.11( from same Table)
C
12
The pvalue printed in the same Table is 0.0033, clearly < 0.01
E
13
The problem asks to test
if proportion of men is larger than
proportion women so
Ha: p(m) >p(f)
A
14
Calculated value of Test Statistic is
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 Spring '09
 staff
 Statistics, Normal Distribution, Statistical hypothesis testing, Output Table, FTR Ho

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