0
votes
1answer
6 views

some knowledge about comare means of two group

I'm studying a bout statistic. I can compute very well. But i don't really know well. I want to know clearly about theory. And i have this problem: ...
0
votes
1answer
30 views

How do I find $\theta$ with bootstrap?

I have two vectors of known values $x$ and $y$. And the relationship between them is $y=\sin(\theta \cdot x)+\epsilon$, $\epsilon \sim N(0,1) $ . The question is how do I estimate $\theta$ with ...
0
votes
1answer
11 views

Comparision between two random samples

I have the following simple random samples which denote the scores obtained by some students over $10$: Random sample A: 3.5 4.5 4.813 5.065 5.252 5.438 5.547 5.586 5.937 6.025 6.025 6.345 6.375 ...
-1
votes
2answers
29 views

Question about Bernoulli Distribution calculation

can sombody explain the above calculation in the red circle marked with "why?"? I am studying MLE with Bernoulli Distribution, and in the middle of a video clip, the lecturer says $ 1\over{n} ...
1
vote
1answer
22 views

Confidence level of random sample from continuous distribution

Let X1,X2,⋯,Xn be a random sample from a continuous distribution with median μ. If [Xmin, Xmax] is used as a confidence interval for μ, what is its confidence level? What is the confidence level if ...
0
votes
0answers
21 views

Multiple comparisons Bonferroni

I want to use Bonferroni method to do multiple comparisons, but i would like to know how the statistic is being proved. From what i understood the statistic of Bonferroni is $$ t=\dfrac{(X_i - X_j )} ...
1
vote
2answers
47 views

Estimating the mean with least median of squares target

I have a set of real numbers $x_1,\ldots,x_n$. I would like estimate the mean of the set, $y$, such that the median of squares will be minimal : $\operatorname{median}(x_i-y)^2$ Is there a closed ...
3
votes
1answer
46 views

Survey: prove 10% of population “Don't know”?

I have a simple question that I expect is a standard situation, but I can't seem to find the right answer (maybe because it's too simple). I have a survey with the following answers: (What is your ...
1
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2answers
76 views

Help needed…Statistics probability and z table…stuck

The question is: **An estimated 1.8 million students take on student loans to pay ever-rising tuition and room and board (New York Times, April 17, 2009). It is also known that the average cumulative ...
1
vote
1answer
133 views

Stuck…please help to understand how formula works in order to Find the standard deviation in normal distributions

A young investment manager tells his client that the probability of making a positive return with his suggested portfolio is 81%. What is the risk (standard deviation) that this investment manager has ...
0
votes
1answer
121 views

statistcs z-table standard deviation question…Please help.

A young investment manager tells his client that the probability of making a positive return with his suggested portfolio is 81%. What is the risk (standard deviation) that this investment manager has ...
0
votes
1answer
42 views

Please help ! A bit confused…I need to figure out exactlty what the question is asking me to determine.

Suppose that over a certain period prices of stocks in the S&P 500 can be approximately modeled using the normal distribution with $\mu = \$40.35$ and a standard deviation of $\$8.97$. The data ...
0
votes
0answers
40 views

What are meaningful properties of a comparison of 2 CDFs?

It's been a while since I've done inferential statistics. I'd appreciate kick-start. I made performance observations that I could line up to f1 as illustrated in the attached photo. Afterwards I ...
1
vote
2answers
232 views

Alternative Hypotheses with equal sign

I have been having some trouble formalizing the hypotheses for an experiment. My claim, it's not this one, but it basically poses the same problem I am having: Studying math in the morning or in ...
0
votes
0answers
31 views

Tst of hypothesis

I just want you to check whether ı am correct or not please can you check.
1
vote
3answers
170 views

Simple standard deviation question using stocks as example

The following table is from page 171 of Fundamentals of Investing (11th edition) by Gitman, Joehnk, Smart. Please consider only the X, Y and XY columns (second, third, fifth). Portfolio XY comprises ...