Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [statistics]

Mathematical statistics is the study of statistics from a mathematical standpoint, using probability theory and other branches of mathematics such as linear algebra and analysis.

Statistics is the science of the collection, organization, and interpretation of data. It deals with many aspects of data, which includes the planning of data collection in terms of the design of surveys and experiments. (From Wikipedia)

More specifically, mathematical statistics is the study of statistics from a mathematical standpoint, using probability theory as well as other branches of mathematics such as linear algebra and mathematical analysis. (From Wikipedia)

For questions which are more generally about collecting and treating data, it is advised that you post your question on Cross Validated and DSSE.

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Why is it answer Stratified random sampling

Forty seven math majors, 22 music majors and 31 history majors are randomly selected from 585 math majors, 279 music majors and 393 history majors at the state university. What sampling technique is used? Answer: stratified Why is it stratified and…
manual
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Binomial and Variance (again)

$\newcommand{\Var}{\operatorname{Var}}$ I guess the answer is extremely easy, but I think I've missed something... When we have a set of $n$ independent identically distributed variables (with the binomial distribution), we can deduce the variance…
faero
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Statistics Confidence Interval Estimators

I'm working on this problem and don't know how to approach it: problem http://puu.sh/5B36g.png Could anyone help steer me in the right direction? Thanks
Richard
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Bias of the Kernel density estimator without bounded support of the Kernel

This is a standard result and should be easy to prove. Yet I cannot figure out the final step. Consider the Kernel density estimator: $\hat f_h=\frac{1}{nh}\sum K\left(\frac{X_i-x}{h}\right)$ where $X_i \sim iid$ with density $f$ K integrable with…
Murray
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Statistical Test for Two Group Means

I've got two group means and I want to see if the difference is statistically significant. I'm using US Census data and race. For instance, I'll have one group of 100 people that is 50% white and another group of 50 people that is 70% white. What…
Aaron Kreider
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Working out percentages from other percentages - no raw data

I'm having some difficulty trying to figure out how to come up with a way to solve my problem. I have the following information: 12% of men do X activity 26% of women do X activity 28% of 25-34 years olds do X activity I want to find out what…
user111086
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Ranking algorthim for views/likes/dislikes

I have a table of data that records the number of views an item receives by users viewing the content and the number of likes and dislikes that the users gave: ID Views Like Dislikes Rank 1 1000 100 0 2 1000 100 50 3 500 …
AndroidDev
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Nt+1 = λNt ⇔ ΔNt to t+1 = RNt

I'm struggling in my subject that has a component of maths in it, please help. I need to make $N_{t+1} = \lambda Nt$ become $\Delta N_{t\ \text{to}\ t+1} = RN_t$ showing working. $N_{t+1}$ is the population size at time $t+1$. $N_t$ is the…
Renee. S.
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Approximating Distribution of a Data Set

If I have a set of data point and I want to approximate the distribution of that data set. What methods can be employed to fit the data set with the best most distribution. Whether it be gamma, normal, log normal, exponential, etc. I am trying to…
jessica
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Percentile of CDF Function

I am trying to find the 0.5 (mean) percentile of a CDF function. $$ F(X) = 1 - e^{-(x/3)^2} $$ In my book's example it says $$ m = 3[-ln(1-0.5)]^{1/2} = 3\sqrt{ln2}=2.498$$ I am not sure how to get to the above equation even using the definition of…
RulesOfTheGame
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Can I get weighted sample variance from the individual variances?

Suppose I have daily aggregates: mean ($m_i$), variance ($v_i$) and number of samples ($n_i$); and I want to calculate weekly aggregates from these. Weekly mean, $M$, is simple: its just a weighted mean. $$M = \frac{\sum n_i * m_i} {\sum n_i}…
allrite
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Elevated percentage of standard BMI associated with Carcinoma

Percentage of Standard…
Ishihara
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help find my error in a statistics transformation computation

This is a low-priority question, but it has been bugging me so I thought I'd ask. In my stats homework I have the following exercise: Exercise. Suppose $X_1$ and $X_2$ are iid observations from the pdf $f(x\mid\alpha)=\alpha…
Ben W
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Why can't I make this claim about my confidence interval?

Say out of a sample of 200 penguins, I find that 192 of them like chocolate. From this sample data, I create the $95\%$ confidence interval for the proportion of penguins that like chocolate: $$ \left(\frac{192}{200} - 1.96 \times…
David Faux
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estimation of a sample size for a pilot study

I am currently involved in a research project whilst being involved in a statistics programme and I can't quite understand what I have to do...so if anyone could help I would be so very grateful. OK so < need to look at diurnal variation in cortisol…
Jayne
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