Probability and statistics: Measures of central tendency & dispersion
Example P1
=
X
1
N
N
X
∑=
i =1
i
130
= 13
10
Answer C
Example P2
Because there are 10 numbers, the median is the average of the 5th and 6th numbers in an ordered
list, or the average of 1 and 5, or 3.
Answer B
Example P3
The most common value is 1.
Answer A
Probability and statistics: Estimation for a single mean
Example P4
The sample mean is X = 5804 , and for 95% confidence, Zα/2 = 1.96. Then Zα/2σ/n1/2 is 1131.6,
so that the 95% confidence interval is 4672 ≤ µ ≤ 6936.
Answer D
Example P5
The sample mean is X = 5804 , and for n-1 = 2 degrees of freedom, tα/2 = t0.025 = 4.303 (since α
= 0.05). Since the standard deviation is unknown, compute s = 2193.5. Then tα/2s/n1/2 is 5449, so
that the 95% confidence interval is 355 ≤ µ ≤ 11,253.
Answer A
Probability and statistics: Regression and curve fitting
Example P6
Compute Sx = 3, Sy = -1, Sxy = -5, and Sxx = 2. Then b = -5/2 = -2.5, and
a = y − bx =
1
1
S y − bS x ) = ( −1 − (−2.5)(3) ) ≈ 2.17
(
n
3
So, y = 2.17 – 2.5x.
Answer B
Probability and statistics: Expected value in decision making
Example P7
Without knowledge of the weather the expected profit is
E[profit] = p[rain](profit if rain) + p[no rain](profit if no rain) = (0.3)(-100) + (0.7)(200) = $110
Answer B
Computational tools: spreadsheet computations
Answer D
Computational tools: structured programming
AUC exam problem 44
Only GOTO is a branching statement.
Answer B
Ethics and professional responsibility
Example E1
The first canon of the code of ethics, and the model rules, says the responsibility is the public
welfare.
Answer C
AUC problem 47
Answers A and C do not address potential problems of safety. The AUC answer is B, but I would
notify the director and follow up. If no action is taken, then higher authority should be notified.
AUC problem 48
Answer A. B is not because of rule A.5. C is not because of B.6, and D is not because of B.7.
AUC problem 49
Answer A. See rule B.1.
AUC problem 50
Answer C. See the model rules in the FE Handbook.
AUC problem 51
Answer A.
AUC problem 52
The AUC answer is blank!
AUC problem 53
Answer C. See rule B.2.
AUC problem 54
Answer B. See rule A.4.