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Questions and Answers
What is the probability distribution function denoted as in the context of a random variable X?
What is the probability distribution function denoted as in the context of a random variable X?
- F(x) (correct)
- P(X ≤ x)
- p(X)
- f(x)
Which of the following properties is true for a probability distribution function F?
Which of the following properties is true for a probability distribution function F?
- F can be negative.
- F cannot exceed 1. (correct)
- F is always equal to 0.
- F decreases as x increases.
What does a probability mass function (PMF) describe?
What does a probability mass function (PMF) describe?
- The probability that a discrete random variable takes on any value.
- The probability distribution of a discrete random variable. (correct)
- The density of a continuous random variable at a point.
- The probability distribution of a continuous random variable.
In a Bernoulli trial, what outcome corresponds to X=0?
In a Bernoulli trial, what outcome corresponds to X=0?
What is true about the limits of the cumulative distribution function F?
What is true about the limits of the cumulative distribution function F?
What type of random variable does the probability density function (PDF) describe?
What type of random variable does the probability density function (PDF) describe?
Which of the following distributions is NOT commonly associated with a discrete random variable?
Which of the following distributions is NOT commonly associated with a discrete random variable?
What does a Bernoulli random variable assume?
What does a Bernoulli random variable assume?
What is the expected value of a Bernoulli random variable X?
What is the expected value of a Bernoulli random variable X?
What does the variance of a Bernoulli random variable X equal?
What does the variance of a Bernoulli random variable X equal?
What are the possible values of the random variable Sn in a Binomial distribution?
What are the possible values of the random variable Sn in a Binomial distribution?
Which of the following conditions is NOT necessary for a Binomial distribution?
Which of the following conditions is NOT necessary for a Binomial distribution?
What is the probability density function for a Bernoulli random variable f(x)?
What is the probability density function for a Bernoulli random variable f(x)?
Which of the following is true about the sum Sn of Bernoulli trials?
Which of the following is true about the sum Sn of Bernoulli trials?
What is the form of the pdf of a Binomial random variable X?
What is the form of the pdf of a Binomial random variable X?
Which of the following values can p take in the context of Bernoulli random variables?
Which of the following values can p take in the context of Bernoulli random variables?
What is the expected value of a Poisson random variable X?
What is the expected value of a Poisson random variable X?
In a Poisson distribution, what does the parameter λ represent?
In a Poisson distribution, what does the parameter λ represent?
Which of the following statements about variance and standard deviation in a Poisson distribution is true?
Which of the following statements about variance and standard deviation in a Poisson distribution is true?
If a rare disease occurs in 2 percent of a population, what is the value of λ for a sample of 10,000 people?
If a rare disease occurs in 2 percent of a population, what is the value of λ for a sample of 10,000 people?
In the formula $ ext{P}(X
eq 5)$, which time-sensitive event is described?
In the formula $ ext{P}(X eq 5)$, which time-sensitive event is described?
Which exploratory data analysis technique is effective in identifying outliers?
Which exploratory data analysis technique is effective in identifying outliers?
When approximating a binomial distribution with a Poisson distribution, which condition must be true?
When approximating a binomial distribution with a Poisson distribution, which condition must be true?
What feature of data does exploratory data analysis (EDA) primarily focus on?
What feature of data does exploratory data analysis (EDA) primarily focus on?
What is the mean or expected value of a binomial random variable X with parameters n and p?
What is the mean or expected value of a binomial random variable X with parameters n and p?
In a binomial distribution, which of the following conditions must be satisfied?
In a binomial distribution, which of the following conditions must be satisfied?
If a soldier has a probability of hitting a target of 0.8 and fires 10 shots, what is the variance of the number of hits?
If a soldier has a probability of hitting a target of 0.8 and fires 10 shots, what is the variance of the number of hits?
Which formula represents the probability density function for a binomial random variable X?
Which formula represents the probability density function for a binomial random variable X?
What is the probability that a soldier hits a target at least 9 times out of 10 shots, with a hit probability of 0.8?
What is the probability that a soldier hits a target at least 9 times out of 10 shots, with a hit probability of 0.8?
For a random variable with a hypergeometric distribution, which of the following statements is true?
For a random variable with a hypergeometric distribution, which of the following statements is true?
In the context of hypergeometric distribution, what does the term 'k' represent?
In the context of hypergeometric distribution, what does the term 'k' represent?
What is the probability of obtaining 2 or fewer hearts when selecting 5 cards from a standard deck?
What is the probability of obtaining 2 or fewer hearts when selecting 5 cards from a standard deck?
What type of experiment is described when randomly selecting 5 cards from a deck and counting the number of hearts?
What type of experiment is described when randomly selecting 5 cards from a deck and counting the number of hearts?
Which formula is used to calculate the probability of a hypergeometric random variable?
Which formula is used to calculate the probability of a hypergeometric random variable?
What is the expected value formula for a hypergeometric random variable?
What is the expected value formula for a hypergeometric random variable?
What does the variable $ ext{λ}$ represent in the context of the Poisson random variable?
What does the variable $ ext{λ}$ represent in the context of the Poisson random variable?
Which of the following formulas correctly defines the probability density function of a Poisson variable?
Which of the following formulas correctly defines the probability density function of a Poisson variable?
In a hypergeometric distribution, what is the relationship between the variance and the number of trials?
In a hypergeometric distribution, what is the relationship between the variance and the number of trials?
Which condition qualifies an event as a rare event in a Poisson experiment?
Which condition qualifies an event as a rare event in a Poisson experiment?
What is the standard deviation formula for a hypergeometric random variable?
What is the standard deviation formula for a hypergeometric random variable?
Flashcards
What is a Cumulative Distribution Function (CDF)?
What is a Cumulative Distribution Function (CDF)?
A function that describes the probability that a random variable takes on a value less than or equal to a given value.
Describe key properties of CDF F(x).
Describe key properties of CDF F(x).
A non-decreasing function that takes on values between 0 and 1. It reflects the likelihood of a random variable being less than or equal to a given value.
What is a Probability Mass Function (PMF)?
What is a Probability Mass Function (PMF)?
It describes the probability distribution of a discrete random variable. It gives the probability of a specific value.
What is a Probability Density Function (PDF)?
What is a Probability Density Function (PDF)?
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What is a Bernoulli Trial?
What is a Bernoulli Trial?
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What is a Bernoulli Random Variable?
What is a Bernoulli Random Variable?
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What is a Bernoulli Distribution?
What is a Bernoulli Distribution?
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What is a Binomial Distribution?
What is a Binomial Distribution?
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Bernoulli Random Variable
Bernoulli Random Variable
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Probability of Success (p)
Probability of Success (p)
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Probability of Failure (1-p)
Probability of Failure (1-p)
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Expected Value of a Bernoulli Random Variable (E[X])
Expected Value of a Bernoulli Random Variable (E[X])
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Variance of a Bernoulli Random Variable (Var[X])
Variance of a Bernoulli Random Variable (Var[X])
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Binomial Random Variable
Binomial Random Variable
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Binomial Probability (P(X = x))
Binomial Probability (P(X = x))
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Conditions for Binomial Distribution
Conditions for Binomial Distribution
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Binomial Probability
Binomial Probability
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Expectation of a Binomial Variable
Expectation of a Binomial Variable
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Variance of a Binomial Variable
Variance of a Binomial Variable
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Standard Deviation of a Binomial Variable
Standard Deviation of a Binomial Variable
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Hypergeometric Random Variable
Hypergeometric Random Variable
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Hypergeometric Probability
Hypergeometric Probability
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Hypergeometric Distribution
Hypergeometric Distribution
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Expected Value of a Poisson Variable (E[X])
Expected Value of a Poisson Variable (E[X])
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Variance of a Poisson Variable (Var[X])
Variance of a Poisson Variable (Var[X])
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Standard Deviation of a Poisson Variable (SD[X])
Standard Deviation of a Poisson Variable (SD[X])
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Probability of At Least Two Occurrences of a Rare Event
Probability of At Least Two Occurrences of a Rare Event
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Approximation of Binomial Distribution using Poisson Distribution
Approximation of Binomial Distribution using Poisson Distribution
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Exploratory Data Analysis (EDA)
Exploratory Data Analysis (EDA)
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Normal Random Variable with Mean μ and Variance σ²
Normal Random Variable with Mean μ and Variance σ²
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Z-Score Formula (Z = (X - μ) / σ)
Z-Score Formula (Z = (X - μ) / σ)
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Hypergeometric Experiment
Hypergeometric Experiment
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Expected Value of a Hypergeometric Variable
Expected Value of a Hypergeometric Variable
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Variance of a Hypergeometric Variable
Variance of a Hypergeometric Variable
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Standard Deviation of a Hypergeometric Variable
Standard Deviation of a Hypergeometric Variable
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Rare Event
Rare Event
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Poisson Distribution
Poisson Distribution
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Study Notes
Course Information
- Course Title: Probability I
- Course Code: STA 112
- University: Bowen University
- Location: Iwo, Nigeria
- College: College of Agriculture, Engineering and Sciences
- Credits: 3
- Instructor: Daniel Akinboro
- Program: Statistics Programme
Probability Distribution Function
- Let X be a random variable with probability density function f(x).
- The probability distribution function, F(x), is defined as Σf(y) for x real, where the summation is over all y ≤ x.
- F(x) = P(X ≤ x)
- Properties of the probability distribution function (PDF):
- F is a non-decreasing function. If a < b, then F(a) < F(b).
- Limit as b approaches ∞ of F(b) = 1.
- Limit as b approaches -∞ of F(b) = 0.
- F is right-continuous. This means F(b +) = F(b).
Probability Mass Function (PMF) and Probability Density Function (PDF)
- PMF: Used to describe the probability distribution of a discrete random variable.
- PMF gives the probability that a discrete random variable takes on a specific value.
- PDF: Used to describe the probability distribution of a continuous random variable.
- PDF gives the probability density of a continuous random variable at a specific point.
Probability Distributions
- Bernoulli Distribution: Describes a random variable with only two possible outcomes (success or failure).
- Binomial Distribution: Sum of independent Bernoulli random variables.
- Describes the probability of a specific number of successes in a fixed number of trials.
- Hypergeometric Distribution: Describes the probability of a specific number of successes in a fixed number of draws without replacement from a finite population.
- Poisson Distribution: Describes the probability of a specific number of events in a fixed interval of time or space.
- Normal Distribution: A continuous probability distribution. Has a characteristic bell shape. Specified by mean and variance.
Bernoulli Random Variables (cont.)
- Probability Density Function (PDF) of X is:
- P(X = 1) = p, P(X = 0) = 1 - р
- f(x) = px(1 - p)1-x, x = 0, 1 (0 ≤ p ≤ 1)
- f(x) = 0 elsewhere
- Expectation, Variance and Standard Deviation of a Bernoulli random variable X:
- E(X) = p
- Var(X) = p(1 – p)
- SD(X) = √p(1 - p)
Binomial Random Variable
- Describes the number of successes in n independent Bernoulli trials.
- Probability of success in each trial is p.
- Possible values of the variable range from 0 to n.
- Parameters: n (number of trials) and p (probability of success).
Binomial Random Variable (cont.)
- Definition: A discrete random variable X, denoting the total number of successes in n trails, is said to have the binomial distribution if :
- P(X = x) = nCx * px * (1-p)n-x where x = 0, 1, ..., n, and 0 ≤ p ≤ 1
- Conditions for a Binomial Distribution:
- Fixed number of trials
- Only two possible outcomes (success or failure)
- Independent trials
- Constant probability of success
Binomial Random Variable (cont.)
- Expectation and Variance of a Binomial Random Variable X:
- E(X) = np
- Var(X) = np(1 - p)
- SD(X) = √np(1 - p)
Hypergeometric Random Variable
- Describes the probability of drawing exactly x successes from a population of N items, where k of these are successes, and n items are drawn.
- Formula: P(X = x; N, n, k) = kCx * (N – k)Cn – x/ NCn
Hypergeometric Random Variable (cont.)
- Expectation and Variance of a Hypergeometric random variable X:
- E(X) = nk/N
- Var(X) = nk(N – k)(N – n)/N²(N – 1)
- SD(X) = √nk(N – k)(N – n)/N²(N – 1)
Poisson Random Variable
- Describes the probability of a specific number of events in a given interval, when the events are rare.
- The probability of an event happening is very small, while the number of trials is large.
- Formula: P(X = x) = (λ^x * e^-λ)/x! , where x = 0, 1, 2,...
Poisson Random Variable (cont.)
- Example of a rare event:
- Rate of accidents per month
- Calculating parameters
- Using the rate of the occurrence of events or successes over a specific time interval
- Mean or average rate (λ)
- Variance and standard deviation is equal to λ
- Probability distribution of occurrence of events.
Normal Random Variable
- A continuous random variable with a characteristic bell-shaped distribution.
- Defined by its mean (μ) and variance (σ²).
- Probability Density Function (PDF):
- f(x; μ, σ²) =1/√(2 π σ²) * e ^(-(x-μ)² / (2σ²))
Normal Random Variable (cont.)
- Standardized Normal Distribution: A normal distribution with a mean of 0 and a standard deviation of 1.
Exploratory Data Analysis (EDA)
- Involves analyzing and visualizing data to understand its underlying structure, patterns and relationships.
- Techniques include histograms, scatter plots, and box plots.
- Helps identify outliers, trends and potential variables.
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