() WGU C955 Probability and Statistics
Objective Assessment (2 Different Version Exam)
Questions and Answers, 100% Guarantee Pass
1.
Question: Which of the following measures is most affected by outliers?
A. Mean
B. Median
C. Mode
D. Interquartile range
-answer :A
Explanation: The mean is sensitive to extreme values because it takes into
,account every value in the data set. The median and mode are resistant to
outliers. The interquartile range is based on quartiles which are also resistant.
2. Question: In a symmetric distribution, which of the following is true?
A. Mean = Median = Mode
B. Mean > Median > Mode
C. Mean < Median < Mode
D. None of the above
-answer :A
Explanation: For a perfectly symmetric distribution (like normal
distribution), the mean, median, and mode are all equal.
3. Question: The probability of an event is always between:
A. -1 and 1
B. 0 and 1
C. 0 and 100
D. 0 and infinity
-answer :B
Explanation: By definition, probability ranges from 0 (impossible) to 1
(certain). Sometimes expressed as percentages from 0% to 100%, but the
numerical value is between 0 and 1.
4. Question: If two events A and B are mutually exclusive, what is P(A and B)?
A. 0
B. P(A) * P(B)
C. P(A) + P(B)
D. 1
-answer :A
Explanation: Mutually exclusive events cannot occur together, so the
probability of both occurring is 0.
5. Question: The complement of an event A is:
A. 1 - P(A)
B. P(A) - 1
C. P(A) * (1 - P(A))
D. P(A) + P(not A)
-answer :A
, Explanation: The sum of probabilities of an event and its complement is 1,
so P(not A) = 1 - P(A).
6. Question: Which of the following is a discrete random variable?
A. Height of students in a class
B. Time to run a marathon
C. Number of cars in a parking lot
D. Weight of packages
-answer :C
Explanation: Discrete variables are countable (like number of cars). The
others are continuous measurements.
7. Question: For a normal distribution, what percentage of data falls within
one standard deviation of the mean?
A. 50%
B. 68%
C. 95%
D. 99.7%
-answer :B
Explanation: The empirical rule states that for a normal distribution,
approximately 68% of data falls within one standard deviation (mean ± σ),
95% within two, and 99.7% within three.
8. Question: The correlation coefficient r measures:
A. Causation between two variables
B. The strength and direction of a linear relationship
C. The slope of the regression line
D. The difference between observed and predicted values
-answer :B
Explanation: Correlation measures the strength and direction of linear
association, but does not imply causation.
9. Question: In hypothesis testing, the p-value is:
A. The probability that the null hypothesis is true
B. The probability of obtaining a test statistic at least as extreme as the one
observed, assuming the null hypothesis is true
C. The probability that the alternative hypothesis is true
, D. The probability of Type I error
-answer :B
Explanation: The p-value is the probability, under the null hypothesis, of
obtaining a result equal to or more extreme than what was observed.
10.Question: A Type I error occurs when:
A. We reject a true null hypothesis
B. We fail to reject a false null hypothesis
C. We reject a false null hypothesis
D. We fail to reject a true null hypothesis
-answer :A
Explanation: Type I error is rejecting the null when it is true. Type II error is
failing to reject when it is false.
11.Question: Which of the following is a measure of central tendency?
A. Range
B. Variance
C. Standard deviation
D. Median
-answer :D
Explanation: Measures of central tendency include mean, median, mode.
The others are measures of dispersion.
12.Question: The interquartile range (IQR) is:
A. The difference between the maximum and minimum values
B. The difference between the third quartile and first quartile
C. The range of the middle 50% of the data
D. Both B and C
-answer :D
Explanation: IQR = Q3 - Q1, and it represents the spread of the middle 50%
of data.
13.Question: If a dataset has a mean of 50 and a standard deviation of 5, what
is the z-score for a value of 60?
A. 1
B. 2
C. -2
Objective Assessment (2 Different Version Exam)
Questions and Answers, 100% Guarantee Pass
1.
Question: Which of the following measures is most affected by outliers?
A. Mean
B. Median
C. Mode
D. Interquartile range
-answer :A
Explanation: The mean is sensitive to extreme values because it takes into
,account every value in the data set. The median and mode are resistant to
outliers. The interquartile range is based on quartiles which are also resistant.
2. Question: In a symmetric distribution, which of the following is true?
A. Mean = Median = Mode
B. Mean > Median > Mode
C. Mean < Median < Mode
D. None of the above
-answer :A
Explanation: For a perfectly symmetric distribution (like normal
distribution), the mean, median, and mode are all equal.
3. Question: The probability of an event is always between:
A. -1 and 1
B. 0 and 1
C. 0 and 100
D. 0 and infinity
-answer :B
Explanation: By definition, probability ranges from 0 (impossible) to 1
(certain). Sometimes expressed as percentages from 0% to 100%, but the
numerical value is between 0 and 1.
4. Question: If two events A and B are mutually exclusive, what is P(A and B)?
A. 0
B. P(A) * P(B)
C. P(A) + P(B)
D. 1
-answer :A
Explanation: Mutually exclusive events cannot occur together, so the
probability of both occurring is 0.
5. Question: The complement of an event A is:
A. 1 - P(A)
B. P(A) - 1
C. P(A) * (1 - P(A))
D. P(A) + P(not A)
-answer :A
, Explanation: The sum of probabilities of an event and its complement is 1,
so P(not A) = 1 - P(A).
6. Question: Which of the following is a discrete random variable?
A. Height of students in a class
B. Time to run a marathon
C. Number of cars in a parking lot
D. Weight of packages
-answer :C
Explanation: Discrete variables are countable (like number of cars). The
others are continuous measurements.
7. Question: For a normal distribution, what percentage of data falls within
one standard deviation of the mean?
A. 50%
B. 68%
C. 95%
D. 99.7%
-answer :B
Explanation: The empirical rule states that for a normal distribution,
approximately 68% of data falls within one standard deviation (mean ± σ),
95% within two, and 99.7% within three.
8. Question: The correlation coefficient r measures:
A. Causation between two variables
B. The strength and direction of a linear relationship
C. The slope of the regression line
D. The difference between observed and predicted values
-answer :B
Explanation: Correlation measures the strength and direction of linear
association, but does not imply causation.
9. Question: In hypothesis testing, the p-value is:
A. The probability that the null hypothesis is true
B. The probability of obtaining a test statistic at least as extreme as the one
observed, assuming the null hypothesis is true
C. The probability that the alternative hypothesis is true
, D. The probability of Type I error
-answer :B
Explanation: The p-value is the probability, under the null hypothesis, of
obtaining a result equal to or more extreme than what was observed.
10.Question: A Type I error occurs when:
A. We reject a true null hypothesis
B. We fail to reject a false null hypothesis
C. We reject a false null hypothesis
D. We fail to reject a true null hypothesis
-answer :A
Explanation: Type I error is rejecting the null when it is true. Type II error is
failing to reject when it is false.
11.Question: Which of the following is a measure of central tendency?
A. Range
B. Variance
C. Standard deviation
D. Median
-answer :D
Explanation: Measures of central tendency include mean, median, mode.
The others are measures of dispersion.
12.Question: The interquartile range (IQR) is:
A. The difference between the maximum and minimum values
B. The difference between the third quartile and first quartile
C. The range of the middle 50% of the data
D. Both B and C
-answer :D
Explanation: IQR = Q3 - Q1, and it represents the spread of the middle 50%
of data.
13.Question: If a dataset has a mean of 50 and a standard deviation of 5, what
is the z-score for a value of 60?
A. 1
B. 2
C. -2
