IEE 380 QUIZZES QUESTIONS & ANSWERS
Historical data is used if you are doing a _________ study. - Answer -Retrospective
If you go out to collect data to analyze, this would be an example of a ________ study. -
Answer -observational
The Addition Rule states that P(A U B) = P(A) + P(B) - _________. - Answer -P(A∩B)
The variance formula for a random variable with the Discrete Uniform pmf will only work
if the values of the random variable are __________ integers. - Answer -Consecutive
Recall that in class, we talked about discrete and continuous random variables. Which
of the follwoing would be a good example of a continuous random variable?
a) Number of defects on a circuit board.
b) Number of cars passing in an intersection.
c) A student's GPA as reported on their transcript.
d) The face value for the throw of a fair die.
e) The height of a person - Answer -Height
Consider a discrete random variable. Which of the following, when plotted will look like
stairs going up and to the right? - Answer -F(X)
Consider a discrete random variable X, with range x= 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. P(X
< 10) = F( ). What number should be in the parenthesis after "F"? - Answer -9
Width measuremetns of a steel bar are made to the nearest hundreth of a millimeter.
The thickness measurements are discrete uniformly distributed with values 1mm, 2mm,
3mm, and 4mm. E(X) = 2.5 mm.
a) What is the expected value of a discrete random variable, X.
b) What is the units? - Answer -a) 2.5
b) mm
Which of the following probability distributions often determines the probabilities of a
counting process? - Answer -Poisson Distribution
An electronic product contains 51 integrated circuits. The probability that any integrated
circuit is defective is 0.01, and the integrated circuits are independent. Suppose you
want to determine the probability that the number of defective circuits in this product is
equal to 2. The best definition of the random variable, X, in words is: - Answer -X is the
number of defective integrated circuits out of 51 integrated circuits.
Explanation: X is a binomial random variable, not a probability.
, We know that ________ will always have one of two outcomes. - Answer -A Bernoulli
Trial
A side door panel on a vehicle is produced at Acme Co. Twenty-five of these doors are
inspected to determine if they pass or fail. The probability that a door passes is 0.83.
Suppose you want to determine the probability that the number of doors that pass our of
these 25 is equal to 19. The best definition of the random variable, X, in words is: -
Answer -X is the number of doors out of 25 that pass.
p(x) is the notation for pmf of a discrete random variable. We also know that F(X) is the
notation for a CDF, the cumulative distribtuion function. If X is a discrete random
variable, what is true?
a) F(X) >= p(X)
b) F(x) and p(x) can be negative
c) p(x) and F(X) can be > 1
d) p(x) and F(x) represent the same quantities for all values of x.
e) p(x) >= F(X) - Answer -a) F(X) >= p(X)
T or F: X is the weight in grams of a gear used in the rotary mechanism of a microwave
oven. The pdf is given as f(x) = 1/3 for 3.5 gram < x < 6.5 grams. X is a continuous
variable. - Answer -True
X is the weight in grams of a gear used in the rotary mechanism of a microwave oven.
The pdf is given as f(x) = 1/3 for 3.5 gram < x < 6.5 grams. The probability that the
weight of one of these parts is equal to 5 grams is: - Answer -0
A standard normal variable is ________. - Answer -A Contnuous Random Variable
The probability that random variable Z = 0 is: - Answer -0
E(X^2) - [E(X)]^2 is: - Answer -The variance of x
T or F: Both Z and T have ranges from -infinity to +infinity. - Answer -True
Suppose we have a random variable, X, that is normally distributed with a mean equal
to u and a standard deviation equal to std. The standard error of the sample mean is: -
Answer -std / sqrt(n)
Suppose we have a random variable, X, that is normally distributed with a mean equal
to u and a standard deviation equal to std. A sample of n is taken from this distribution.
E(X-bar) = - Answer -E(X)
Which of the following is true about Chi-Square random variable?
a) The area under its pdf is equal to 1/2.
b) It cannot be negative.
c) It is symmetric
Historical data is used if you are doing a _________ study. - Answer -Retrospective
If you go out to collect data to analyze, this would be an example of a ________ study. -
Answer -observational
The Addition Rule states that P(A U B) = P(A) + P(B) - _________. - Answer -P(A∩B)
The variance formula for a random variable with the Discrete Uniform pmf will only work
if the values of the random variable are __________ integers. - Answer -Consecutive
Recall that in class, we talked about discrete and continuous random variables. Which
of the follwoing would be a good example of a continuous random variable?
a) Number of defects on a circuit board.
b) Number of cars passing in an intersection.
c) A student's GPA as reported on their transcript.
d) The face value for the throw of a fair die.
e) The height of a person - Answer -Height
Consider a discrete random variable. Which of the following, when plotted will look like
stairs going up and to the right? - Answer -F(X)
Consider a discrete random variable X, with range x= 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. P(X
< 10) = F( ). What number should be in the parenthesis after "F"? - Answer -9
Width measuremetns of a steel bar are made to the nearest hundreth of a millimeter.
The thickness measurements are discrete uniformly distributed with values 1mm, 2mm,
3mm, and 4mm. E(X) = 2.5 mm.
a) What is the expected value of a discrete random variable, X.
b) What is the units? - Answer -a) 2.5
b) mm
Which of the following probability distributions often determines the probabilities of a
counting process? - Answer -Poisson Distribution
An electronic product contains 51 integrated circuits. The probability that any integrated
circuit is defective is 0.01, and the integrated circuits are independent. Suppose you
want to determine the probability that the number of defective circuits in this product is
equal to 2. The best definition of the random variable, X, in words is: - Answer -X is the
number of defective integrated circuits out of 51 integrated circuits.
Explanation: X is a binomial random variable, not a probability.
, We know that ________ will always have one of two outcomes. - Answer -A Bernoulli
Trial
A side door panel on a vehicle is produced at Acme Co. Twenty-five of these doors are
inspected to determine if they pass or fail. The probability that a door passes is 0.83.
Suppose you want to determine the probability that the number of doors that pass our of
these 25 is equal to 19. The best definition of the random variable, X, in words is: -
Answer -X is the number of doors out of 25 that pass.
p(x) is the notation for pmf of a discrete random variable. We also know that F(X) is the
notation for a CDF, the cumulative distribtuion function. If X is a discrete random
variable, what is true?
a) F(X) >= p(X)
b) F(x) and p(x) can be negative
c) p(x) and F(X) can be > 1
d) p(x) and F(x) represent the same quantities for all values of x.
e) p(x) >= F(X) - Answer -a) F(X) >= p(X)
T or F: X is the weight in grams of a gear used in the rotary mechanism of a microwave
oven. The pdf is given as f(x) = 1/3 for 3.5 gram < x < 6.5 grams. X is a continuous
variable. - Answer -True
X is the weight in grams of a gear used in the rotary mechanism of a microwave oven.
The pdf is given as f(x) = 1/3 for 3.5 gram < x < 6.5 grams. The probability that the
weight of one of these parts is equal to 5 grams is: - Answer -0
A standard normal variable is ________. - Answer -A Contnuous Random Variable
The probability that random variable Z = 0 is: - Answer -0
E(X^2) - [E(X)]^2 is: - Answer -The variance of x
T or F: Both Z and T have ranges from -infinity to +infinity. - Answer -True
Suppose we have a random variable, X, that is normally distributed with a mean equal
to u and a standard deviation equal to std. The standard error of the sample mean is: -
Answer -std / sqrt(n)
Suppose we have a random variable, X, that is normally distributed with a mean equal
to u and a standard deviation equal to std. A sample of n is taken from this distribution.
E(X-bar) = - Answer -E(X)
Which of the following is true about Chi-Square random variable?
a) The area under its pdf is equal to 1/2.
b) It cannot be negative.
c) It is symmetric
