WGU C955 Applied Probability and Statistics Final Practice
Exam Prep Document | 2026/2027 Edition | 150 Verified
Questions - 110 Questions with Answers
WGU C955 Applied Probability and Statistics Final Exam 2026-110 QUESTIONS AND ANSWERS ALREADY
GRADED A+. 100% Verified Solutions | Updated Per Latest Guidelines | Graded A+
This comprehensive practice exam document is meticulously crafted for students preparing for the
WGU C955 Applied Probability and Statistics final exam. It contains 150 verified questions with
detailed answers and rationales, reflecting the most current curriculum and assessment standards.
Designed to reinforce key concepts and boost confidence, this resource is an essential tool for
achieving a top grade.
Key Features:
Descriptive Statistics and Data Visualization
Probability Theory and Distributions
Sampling Distributions and Estimation
Hypothesis Testing and Confidence Intervals
Correlation and Regression Analysis
Chi-Square Tests and Nonparametric Methods
Updates for 2026:
- Updated to align with the 2026/2027 WGU C955 course objectives
- Incorporated the latest question formats and difficulty levels
- Enhanced answer rationales for deeper conceptual understanding
- Added new practice questions covering emerging statistical applications
- Revised content to reflect current exam weighting and topic emphasis
Abstract:
The WGU C955 Applied Probability and Statistics final practice exam is a rigorous compilation of 150 questions
designed to assess mastery of fundamental statistical concepts and their practical applications. The document
covers descriptive statistics, including measures of central tendency and variability, and graphical representations
of data. It delves into probability theory, discrete and continuous distributions, and the central limit theorem.
Inferential statistics are thoroughly addressed through sampling distributions, confidence intervals, and hypothesis
testing for one and two populations. The material also explores correlation, simple linear regression, and
chi-square tests for independence and goodness-of-fit. Each question is accompanied by a detailed answer and
rationale, facilitating self-assessment and targeted review. This resource is indispensable for students aiming to
excel in the WGU C955 final examination.
Keywords:
Applied Probability, Statistics, WGU C955, Practice Exam, Graded A+, 2026/2027, Verified Questions, Detailed
Answers
Answer Format:
Each question is followed by the correct answer and a comprehensive explanation that clarifies the underlying
statistical principle. Distractor explanations are provided to illuminate common misconceptions and reinforce
learning. Rationales are written in a clear, scholarly style to support deep understanding.
Compliance Checklist:
Aligned with WGU C955 course competencies
Page 1
, Reflects 2026/2027 exam blueprint and weighting
All 150 questions verified and accurate
Detailed rationales for every answer
Suitable for self-study and exam review
Content Area Overview:
Content Area Questions Key Topics Weight
Descriptive Statistics and Data 1-25 Measures of central tendency, measures of 17%
Visualization variability, frequency distributions,
histograms, boxplots
Probability Theory and 26-55 Basic probability rules, conditional 20%
Distributions probability, discrete distributions (binomial,
Poisson), continuous distributions (normal,
uniform)
Sampling Distributions and 56-75 Central limit theorem, sampling distribution 13%
Estimation of the mean, point estimation, confidence
intervals for means and proportions
Hypothesis Testing and 76-105 Null and alternative hypotheses, Type I and 20%
Confidence Intervals II errors, one-sample and two-sample tests,
p-values, confidence intervals
Correlation and Regression 106-130 Scatterplots, correlation coefficient, least 17%
Analysis squares regression, interpretation of slope
and intercept, prediction
Chi-Square Tests and 131-150 Chi-square goodness-of-fit, chi-square test 13%
Nonparametric Methods of independence, sign test, Wilcoxon
rank-sum test
Page 2
,Q1. A data scientist is analyzing the distribution of customer transaction amounts.
The data are heavily right-skewed with several extreme outliers. Which measure of
central tendency and dispersion should be reported to best summarize the typical
transaction and variability?
A. Mean and standard deviation
B. Median and interquartile range
C. Mode and range
D. Geometric mean and variance
Correct Answer: B. Median and interquartile range
Rationale: For heavily skewed data with outliers, the median and interquartile range are
robust measures that are not unduly influenced by extreme values. The mean and standard
deviation are sensitive to outliers, while the mode and range provide limited information.
Why Wrong:
A - Mean and standard deviation are pulled by outliers, misrepresenting the typical
value and variability.
C - Mode and range ignore the shape of the distribution and are not robust to outliers.
D - Geometric mean is for multiplicative data, and variance is still outlier-sensitive.
Reference: WGU C955, Descriptive Statistics
Q2. In a clinical trial, the probability that a patient responds to Treatment A is 0.6,
and to Treatment B is 0.5. The probability that a patient responds to both is 0.3.
Given that a patient responded to at least one treatment, what is the probability they
responded to both?
A. 0.3
B. 0.5
C. 0.375
D. 0.6
Correct Answer: C. 0.375
Rationale: Using conditional probability: P(Both | At least one) = P(Both) / P(At least
one). P(At least one) = 0.6 + 0.5 - 0.3 = 0.8. Thus, 0..8 = 0.375.
Why Wrong:
A - 0.3 is the unconditional probability of responding to both, not conditional on at
least one.
B - 0.5 is the marginal probability of responding to Treatment B.
D - 0.6 is the marginal probability of responding to Treatment A.
Reference: WGU C955, Probability Rules
Page 3
, Q3. A random variable X follows a normal distribution with mean 100 and standard
deviation 15. If a sample of size 25 is taken, what is the probability that the sample
mean exceeds 105? (Assume the population is normally distributed.)
A. 0.0475
B. 0.3707
C. 0.6293
D. 0.9525
Correct Answer: A. 0.0475
Rationale: The standard error is 15/"25 = 3. Z = (105 - 100) / 3 = 1.67. P(Z > 1.67) "H
0.0475.
Why Wrong:
B - 0.3707 corresponds to a z-score of 0.33, not 1.67.
C - 0.6293 is the probability of being below 105 (incorrect tail).
D - 0.9525 is the probability of being below 105 using the correct z-score.
Reference: WGU C955, Sampling Distributions
Q4. A researcher wants to estimate the mean IQ score of university professors with
95% confidence and a margin of error of 2 points. Assuming a population standard
deviation of 15, what is the minimum sample size required?
A. 217
B. 216
C. 15
D. 138
Correct Answer: A. 217
Rationale: n = (z*Ã / E)^2. For 95% confidence, z* = 1.96. n = (1.96 * )^2 =
(14.7)^2 = 216.09, round up to 217.
Why Wrong:
B - 216 is the unrounded value; you must round up to ensure the margin of error is
met.
C - 15 is the population standard deviation, not the sample size.
D - 138 would result from using z* = 1.645 (90% confidence).
Reference: WGU C955, Sample Size Determination
Q5. A manufacturer claims that the mean lifetime of its bulbs is 1,000 hours. A
consumer group tests 36 bulbs and finds a mean of 980 hours with a standard
deviation of 60 hours. At = 0.05, what is the conclusion of the two-tailed test?
A. Reject H0; there is sufficient evidence the mean differs from 1,000.
B. Fail to reject H0; there is not sufficient evidence the mean differs from 1,000.
Page 4
Exam Prep Document | 2026/2027 Edition | 150 Verified
Questions - 110 Questions with Answers
WGU C955 Applied Probability and Statistics Final Exam 2026-110 QUESTIONS AND ANSWERS ALREADY
GRADED A+. 100% Verified Solutions | Updated Per Latest Guidelines | Graded A+
This comprehensive practice exam document is meticulously crafted for students preparing for the
WGU C955 Applied Probability and Statistics final exam. It contains 150 verified questions with
detailed answers and rationales, reflecting the most current curriculum and assessment standards.
Designed to reinforce key concepts and boost confidence, this resource is an essential tool for
achieving a top grade.
Key Features:
Descriptive Statistics and Data Visualization
Probability Theory and Distributions
Sampling Distributions and Estimation
Hypothesis Testing and Confidence Intervals
Correlation and Regression Analysis
Chi-Square Tests and Nonparametric Methods
Updates for 2026:
- Updated to align with the 2026/2027 WGU C955 course objectives
- Incorporated the latest question formats and difficulty levels
- Enhanced answer rationales for deeper conceptual understanding
- Added new practice questions covering emerging statistical applications
- Revised content to reflect current exam weighting and topic emphasis
Abstract:
The WGU C955 Applied Probability and Statistics final practice exam is a rigorous compilation of 150 questions
designed to assess mastery of fundamental statistical concepts and their practical applications. The document
covers descriptive statistics, including measures of central tendency and variability, and graphical representations
of data. It delves into probability theory, discrete and continuous distributions, and the central limit theorem.
Inferential statistics are thoroughly addressed through sampling distributions, confidence intervals, and hypothesis
testing for one and two populations. The material also explores correlation, simple linear regression, and
chi-square tests for independence and goodness-of-fit. Each question is accompanied by a detailed answer and
rationale, facilitating self-assessment and targeted review. This resource is indispensable for students aiming to
excel in the WGU C955 final examination.
Keywords:
Applied Probability, Statistics, WGU C955, Practice Exam, Graded A+, 2026/2027, Verified Questions, Detailed
Answers
Answer Format:
Each question is followed by the correct answer and a comprehensive explanation that clarifies the underlying
statistical principle. Distractor explanations are provided to illuminate common misconceptions and reinforce
learning. Rationales are written in a clear, scholarly style to support deep understanding.
Compliance Checklist:
Aligned with WGU C955 course competencies
Page 1
, Reflects 2026/2027 exam blueprint and weighting
All 150 questions verified and accurate
Detailed rationales for every answer
Suitable for self-study and exam review
Content Area Overview:
Content Area Questions Key Topics Weight
Descriptive Statistics and Data 1-25 Measures of central tendency, measures of 17%
Visualization variability, frequency distributions,
histograms, boxplots
Probability Theory and 26-55 Basic probability rules, conditional 20%
Distributions probability, discrete distributions (binomial,
Poisson), continuous distributions (normal,
uniform)
Sampling Distributions and 56-75 Central limit theorem, sampling distribution 13%
Estimation of the mean, point estimation, confidence
intervals for means and proportions
Hypothesis Testing and 76-105 Null and alternative hypotheses, Type I and 20%
Confidence Intervals II errors, one-sample and two-sample tests,
p-values, confidence intervals
Correlation and Regression 106-130 Scatterplots, correlation coefficient, least 17%
Analysis squares regression, interpretation of slope
and intercept, prediction
Chi-Square Tests and 131-150 Chi-square goodness-of-fit, chi-square test 13%
Nonparametric Methods of independence, sign test, Wilcoxon
rank-sum test
Page 2
,Q1. A data scientist is analyzing the distribution of customer transaction amounts.
The data are heavily right-skewed with several extreme outliers. Which measure of
central tendency and dispersion should be reported to best summarize the typical
transaction and variability?
A. Mean and standard deviation
B. Median and interquartile range
C. Mode and range
D. Geometric mean and variance
Correct Answer: B. Median and interquartile range
Rationale: For heavily skewed data with outliers, the median and interquartile range are
robust measures that are not unduly influenced by extreme values. The mean and standard
deviation are sensitive to outliers, while the mode and range provide limited information.
Why Wrong:
A - Mean and standard deviation are pulled by outliers, misrepresenting the typical
value and variability.
C - Mode and range ignore the shape of the distribution and are not robust to outliers.
D - Geometric mean is for multiplicative data, and variance is still outlier-sensitive.
Reference: WGU C955, Descriptive Statistics
Q2. In a clinical trial, the probability that a patient responds to Treatment A is 0.6,
and to Treatment B is 0.5. The probability that a patient responds to both is 0.3.
Given that a patient responded to at least one treatment, what is the probability they
responded to both?
A. 0.3
B. 0.5
C. 0.375
D. 0.6
Correct Answer: C. 0.375
Rationale: Using conditional probability: P(Both | At least one) = P(Both) / P(At least
one). P(At least one) = 0.6 + 0.5 - 0.3 = 0.8. Thus, 0..8 = 0.375.
Why Wrong:
A - 0.3 is the unconditional probability of responding to both, not conditional on at
least one.
B - 0.5 is the marginal probability of responding to Treatment B.
D - 0.6 is the marginal probability of responding to Treatment A.
Reference: WGU C955, Probability Rules
Page 3
, Q3. A random variable X follows a normal distribution with mean 100 and standard
deviation 15. If a sample of size 25 is taken, what is the probability that the sample
mean exceeds 105? (Assume the population is normally distributed.)
A. 0.0475
B. 0.3707
C. 0.6293
D. 0.9525
Correct Answer: A. 0.0475
Rationale: The standard error is 15/"25 = 3. Z = (105 - 100) / 3 = 1.67. P(Z > 1.67) "H
0.0475.
Why Wrong:
B - 0.3707 corresponds to a z-score of 0.33, not 1.67.
C - 0.6293 is the probability of being below 105 (incorrect tail).
D - 0.9525 is the probability of being below 105 using the correct z-score.
Reference: WGU C955, Sampling Distributions
Q4. A researcher wants to estimate the mean IQ score of university professors with
95% confidence and a margin of error of 2 points. Assuming a population standard
deviation of 15, what is the minimum sample size required?
A. 217
B. 216
C. 15
D. 138
Correct Answer: A. 217
Rationale: n = (z*Ã / E)^2. For 95% confidence, z* = 1.96. n = (1.96 * )^2 =
(14.7)^2 = 216.09, round up to 217.
Why Wrong:
B - 216 is the unrounded value; you must round up to ensure the margin of error is
met.
C - 15 is the population standard deviation, not the sample size.
D - 138 would result from using z* = 1.645 (90% confidence).
Reference: WGU C955, Sample Size Determination
Q5. A manufacturer claims that the mean lifetime of its bulbs is 1,000 hours. A
consumer group tests 36 bulbs and finds a mean of 980 hours with a standard
deviation of 60 hours. At = 0.05, what is the conclusion of the two-tailed test?
A. Reject H0; there is sufficient evidence the mean differs from 1,000.
B. Fail to reject H0; there is not sufficient evidence the mean differs from 1,000.
Page 4
