# Search Results

Results tagged with Search options user 7962
32 results

A routine exercise 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.

When the odds are 1, this means males and females are just as likely of getting into an honor class. So when the odds are 1+1 = 2, this means the odds are now twice as likely or a 100% increase in od …
answered Jun 19 '17 by StatsStudent
The issue here is really about practical significance, rather than statistical significance. In both examples, the results were "statistically significant", but in example 1 the size of the effect (i …
answered Jun 19 '17 by StatsStudent
You both are right. But here's a hint to get the answer in your notes: According to Probability Distributive Laws: \begin{eqnarray*} P[BB\cap(BG\cup BB)] & = & P[(BB\cap BG)\cup(BB\cap BB)] \end{eq …
Here's a hint: what is the formula for the 95% confidence interval? Do any terms in the formula for it look like an estimate of $\sigma_{\epsilon}$?
answered Oct 24 '15 by StatsStudent
I think it might do you some good to review the general formula for the sample variance, $\sum_{i=1}^n(x_i-\bar{x})^2\over{n-1}.$ Then explore how you might be able to algebraically manipulate this f …
answered Mar 21 '15 by StatsStudent
This might be a really dumb question, but in a joint PDF of $X$ and $Y$, $f_{XY}(x,y)$, if the support of a random variable $Y$ depends on $X$, are the two random variables necessarily dependent? For …
asked May 9 '17 by StatsStudent
The design matrix you have set up is not quite right. Since this is a homework problem, I'll give you hints and help you through the problem. The key to setting up your design matrix involves, unders …
answered Jan 24 '16 by StatsStudent
I am continuing the prepare for an exam by reviewing handouts from an old statistics course I took. The handout came with a set of solutions prepared by the instructor, but I suspect that one of the …
asked Apr 22 '17 by StatsStudent
I am about to complete my master's degree in Statistics at a very well-respected university and one which has a top 5 statistics department in the U.S. (all I have left to do is defend my thesis). I …
asked May 13 '17 by StatsStudent
This is a classic Z-test. To calculate a Z-score you simply take your observed sample mean, $\bar{X}_n$ minus your hypothesized value under $H_0: \mu=0$, and divide the result by the standard deviati …
answered Jan 22 '15 by StatsStudent
Given your additional comments, it appears that the x-value is fixed at X=1. So there are two observations at that fixed level of x (for the first row). One observation has a $y$ value of 2 and the …
answered Oct 19 '15 by StatsStudent
From the problem statement, you are given that a sample of $N$ observations are made from a bivariate normal population with correlation coefficient equal to zero. Under these assumptions, the probab …
answered Dec 31 '18 by StatsStudent
I am studying for an exam and have come across this problem: Let the random variables $X$ and $Y$ have the joint pmf: $f_{XY}(x,y)={2\over{n(n+1)}}$ for $y=1, . . . , x$; $x=1, . . . , n$ Find the …
You have to recall that $X_1$ and $X_2$ are Poisson random variables and this means the support for $X_1$ and $X_2$ is 0, 1, 2, etc. for each. In other words, $x_1$ and $x_2$ are integers such that $… answered Feb 11 by StatsStudent I'll provide a hint to your self-study question: A corollary of a classic statistical theorem states that if$\mathbf{x} \sim N_p(\boldsymbol{\mu}, \sigma^2\boldsymbol{I})$,then$\mathbf{Bx}$and$\m …