# Tagged Questions

Please DO NOT USE this tag. Use [t-test] to refer to the test, or [t-distribution] to refer to the distribution.

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### Intuition behind the t-distributions density function

I'm studying about Student's t-distribution and I started to wonder, how would one derive the t-distributions density function (from wikipedia, ...
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### Student's t vs Mann-Whitney U

Trying to choose between these two tests for data I've harvested from Android store. Basically, I want to see if there is any difference in the number of dangerous permissions requested by free vs ...
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### Comparing many means in JMP

I'm trying to compare several sets of experiment data, by comparing means. I read there are several different tests such as Each Pair, Student’s t and All Pairs, Tukey HSD, which give different ...
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### Test with Student's t

What kind of null hypothesis can be tested using a Student's t? It's very likely to be one of the questions of the statistics exam. In order to test a null hypothesis using the Student's t, does it ...
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### Student T CDF - How to read the hypergeometric function formula?

I am trying to program out a couple of statistical formulas with python. I am not concerned with efficiency or the fact that there already are tools to calculate the values, but I am doing it to ...
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### Confusing regarding when to use $z$-statistics vs. $t$-statistics

I was referring to this video lecture for calculating the confidence interval. However, I have some confusion. This guy is using $z$-statistics for the calculation. However, I think it should have ...
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### Asymptotic relative efficiency of median vs mean for Student t distribution

I am looking for a theoretical expression for the ARE of mean and median for student-t distribution against sample size (degree of freedom), exactly the blue curve shown in John Cook's blog. Can ...
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### Significance of difference in means

In “A Comparative Study of Nursing Home Residents …”, Aigner et al. write (p. 20) Acute visits were significantly higher for the nurse practiticoner/physician team at 3.0 visits per year (± 2.4) ...
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### Two questions on significance testing

Suppose you have a population and some measurement which you could do on each member of the population (e.g. the population could be all the people in the world, and the measurement could be height). ...
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### What is the distribution of the difference of two-t-distributions

... and why ? Assuming $X_1$,$X_2$ are independent random-variables with mean $\mu_1,\mu_2$ and variance $\sigma^2_1,\sigma^2_2$ respectively. My basic statistics book tells me that the distribution ...
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### Formula or procedure for computing standard statistical tables such as z table, Student's t-table, or chi-square table

How can the following tables be computed: Chi-Square table Student t-table I'm looking for a formula or procedure used to make these tables. For example: If I have a given 'x'-value, as ...
Let $t_i$ be drawn i.i.d from a Student t distribution with $n$ degrees of freedom, for moderately sized $n$ (say less than 100). Define $$T = \sum_{1\le i \le k} t_i^2$$ Is $T$ distributed nearly as ...