# Questions tagged [self-study]

A routine exercise designed to test one's knowledge; often from a textbook, course, or test used for a class or self-study. This community's policy is to "provide helpful hints" for such questions rather than complete answers.

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### Bayes net probability question

I've made this Bayes net based on a problem and I'm trying to find the probability of W but I'm stuck. I know I probably have to use Bayes theorem backwards through to find $P(W)$, but I'm not sure ...
458 views

### Poisson Distribution vs Binomial Distribution

I have a specific problem here. It is stated as: "Assume that 30% of students in a university take public transportation daily to commute to their college. Suppose 10 of the students are randomly ...
1 vote
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### How to introduce the error bars in text?

I want explictly to state in my written text that the error bars in the current plot and all of the following ones represent the 95% percent of the calculated mean. However, the metric changes in the ...
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### Exam P Sample Problems # 30

The question: A company establishes a fund of 120 from which it wants to pay an amount, C, to any of its 20 employees who achieve a high performance level during the coming year. Each employee has a ...
231k views

### Find expected value using CDF

I'm going to start out by saying this is a homework problem straight out of the book. I have spent a couple hours looking up how to find expected values, and have determined I understand nothing. ...
1 vote
245 views

### How to calculate dimension of weight matrix for a vanilla RNN

Sorry if this is kind of a dumb question but I'm taking the NLP course from Andrew Ng on Coursera and I don't understand how to arrive at the correct answer for a question pertaining to calculating ...
149 views

### Conditional probability, who's right?

i need help with a math problem. Me, and at least two teachers have all done it and gotten different results, so now I'm asking the wise people of the internet for help settling the debate. Here's the ...
28k views

1 vote
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### Conditional Expectation(s) of Multiple Random Variables

I am having a bit of trouble with one of the problems I am working right now. The problem is: "What is $E\left \{ E\left \{ E\left \{ Z \mid X , Y \right \} \right \} \right \}$ ?" During an ...
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### Likelihood function for data with random censoring

The following is from Klein and Moeschberger, p. 76. Let $(T,\delta)$ be a tuple with $T = \min(X,C_r)$ and $\delta = 0$ if the lifetime X is censored and $\delta = 1$ if it is not; $C_r$ denotes the ...
342 views

### Another EM-algorithm problem

I have the following problem: I have a random vector $y$ which has length $l$. The first $z$ bits come from a Bernoulli random variable with parameter $\theta_1$ and the next $l-z$ come from a ...
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### Computing Bayesian model averaged posteriors

The Bayesian model averaged posterior predictive distribution for new data $\tilde{y}$ given training data $y$, across a set of $M$ models $\mathcal{D} = \{D_{1}, ..., D_{M}\}$, is defined as: \begin{...
258 views

### Let $X_1, X_2, X_3 \sim \textrm{Expo}(1)$ distribution. How to compute $\mathrm{P}(X_1 + X_2 \leq rX_3)$?

So let $X_1, X_2, X_3$ be random samples from the $\textrm{Expo}(1)$ distribution. How do I set up the computation for $\mathrm{P}(X_1 + X_2 \leq rX_3 | \sum_{i=1}^n X_i = t)$ where $r, t > 0$? ...
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### Bayes Theorem and Total Probability

I'm back for more help....I'm terrible with conditional probability. Here's a problem from an assignment in a stats course I'm taking: A U.S. Army Corps of Engineers (USACE) study focused on DDT ...