WGU C955 Applied Probability & Statistics
OA Study Guide with Practice Questions
Comprehensive Review for WGU C955 Objective Assessment
May 2025
Introduction
This study guide is designed for students preparing for the WGU C955 Applied Probabil-
ity and Statistics Objective Assessment (OA). It covers essential concepts in probability
theory and distributions, with concise notes and practice questions to reinforce under-
standing. The content is tailored to the OA’s focus on practical applications, including
probability calculations, counting techniques, and discrete and continuous distributions.
Probability Theory Notes
Basic Concepts Probability quantifies the likelihood of an event, ranging from 0 (impos-
sible) to 1 (certain).
• Sample Space: All possible outcomes of an experiment (e.g., {H, T} for a coin toss).
• Event: A specific outcome or set of outcomes (e.g., getting heads).
• Probability Formula: For equally likely outcomes:
Favorable outcomes
P (A) =
Total outcomes
Probability Rules
• Addition Rule: For mutually exclusive events: P (A or B) = P (A) + P (B).
• Multiplication Rule: For independent events: P (A and B) = P (A) · P (B).
P (A and B)
• Conditional Probability: P (A|B) = P (B)
, P (B) ̸= 0.
• Complement Rule: P (A′ ) = 1 − P (A).
Counting Techniques
n!
• Permutations: Ordered arrangements: P (n, r) = (n−r)!
.
1
OA Study Guide with Practice Questions
Comprehensive Review for WGU C955 Objective Assessment
May 2025
Introduction
This study guide is designed for students preparing for the WGU C955 Applied Probabil-
ity and Statistics Objective Assessment (OA). It covers essential concepts in probability
theory and distributions, with concise notes and practice questions to reinforce under-
standing. The content is tailored to the OA’s focus on practical applications, including
probability calculations, counting techniques, and discrete and continuous distributions.
Probability Theory Notes
Basic Concepts Probability quantifies the likelihood of an event, ranging from 0 (impos-
sible) to 1 (certain).
• Sample Space: All possible outcomes of an experiment (e.g., {H, T} for a coin toss).
• Event: A specific outcome or set of outcomes (e.g., getting heads).
• Probability Formula: For equally likely outcomes:
Favorable outcomes
P (A) =
Total outcomes
Probability Rules
• Addition Rule: For mutually exclusive events: P (A or B) = P (A) + P (B).
• Multiplication Rule: For independent events: P (A and B) = P (A) · P (B).
P (A and B)
• Conditional Probability: P (A|B) = P (B)
, P (B) ̸= 0.
• Complement Rule: P (A′ ) = 1 − P (A).
Counting Techniques
n!
• Permutations: Ordered arrangements: P (n, r) = (n−r)!
.
1
