Quiz
1
Please put your answers in the following table.
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2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
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1. The
deflection of two beams follow normal distributions are shown below. Which
statement is true?
Distribution
2 Distribution
1
A)
B)
C)
D)
Cannot
determine
2. For
Distribution 1 in problem 1, the mean value of the deflection is 0.002 m, what
is the probability that the deflection is less than 0.002 m?
A)
< 50%
B)
> 50%
C)
= 50%
D)
Cannot determine
3. The
values of a force (N) acting on a machine from ten measurements are given
below.
86.9 95.7 103.4 135.8 127.7
86.5 130.3 107.3 99.4 107.1
The average of the force is
A)
100.0
N
B)
190.0
N
C)
108.0
N
D)
25.4
N
4. For
problem 3, the standard deviation of the force is
A)
10.1
N
B)
0.0
N
C)
103.2
N
D)
17.68
N
5.
A
mean value indicates the dispersion of a random variable. (True or False)
6.
The
CDF of a random variable cannot be 0. (True or False)
7.
The
crate in equilibrium is subjected to a force 
. The coefficient of friction between the crate and floor is
0.1. The weight of a crate is W lb. Knowing 
,
where 
and 
,
determine the mean and standard deviation of the force F.
F
A)
, 
B)
, 
C)
, 
D)
, 
8.
For
problem 7, what is the probability that the weight is less than 11 lb or 
?
A)
0
B)
50%
C)
97.72%
D)
84.13%
9.
A
crate is subject to two independently and normally distributed random forces 
and 
. If
the two forces act in the same direction, the mean and standard deviation of
the resultant force are
A)
220 N and 10 N, respectively.
B)
110 N and 7 N, respectively.
C)
110 N and 14 N, respectively.
D)
20 N and 10 N, respectively.
10.
For
problem 9, the distribution of the resultant force is also normal. (True or
False)