Questions tagged [descriptive-statistics]
The area of statistics that provides descriptions of data, may it be samples or the population. This includes graphical representations and numerical indicators. No information is inferred from samples about the population, as in inferential statistics.
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Statistical methods to compare 21 theoretical values to experiments
I am testing a theoretical model to compute an entity called the g-shift of diatomic molecules (the g-shift for a given diatomic molecule is expressed as a simple scalar value).
I have calculated the ...
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Uncertainties in measurements widen the normal distribution.
In redistricting (gerrymandering) analysis, a state is divided into districts where district vote shares are written in terms of one of two parties, so if district #1 has a vote share of 40%, it means ...
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Calculate contributions to the change of ratio a/b when be is the sum of a plus other variables
I would like to know how to calculate the change contribution to a ratio a/b where b is equal to a plus other variables: ...
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Average customer value
I have a table with customer purchase data.
|customer | month | Purchase amount | number of days shopped |
|A | jan | 200 | 5|
|A | feb | 250 | 7|
| A |...
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Unclear about the definition of "mutually exclusive"
Google says, "mutually exclusive is a statistical term describing two or more events that cannot happen simultaneously."
But when we say that $n$ events are mutually exclusive, we mean that ...
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distribution of sample mean to sample standard deviation
Noting this question, it is known that the sum of squares of independent identically distributed gaussian random variables is a Noncentral chi-squared distribution. That is great and all, but what ...
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Converting a multivariate linear correlation into a univariate one (predicting real estate prices in NY)
I am building a prediction model of real estate properties in New York based on a few inputs:
Area (size) of the property
Year it was built
Number of bedrooms
Number of parking spots
The data is ...
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Weighted average value for five-point scale survey question
I have a survey question which has response choices on a 5-point scale.
The response choices are:
Not at all, Barely, A bit, Almost always, Completely.
We've assigned a value to each response, ranging ...
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How to estimate the best variance-proxy of a sub-Gaussian distribution from data?
Suppose we have $N$ independently identically distributed (i.i.d.) samples $X_1,\cdots,X_N$ generated from a sub-Gaussian random variable $X \sim \mathbb{P}$. Then by definition there exists the ...
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Given a dataset of N values, how to calculate the position(index) of the value at x percentile
Problem is in the title.
The formula usually given for this is:
Required Index: $\frac{x}{100}\times (N+1)$
I don't understand how this is derived.
why should it not instead be $\frac{Nx}{100}+1$ as $\...
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Incompatible results in finding the variance of random variable
Let $f(x) = 3/64(2x - 2)$ whenever $x \in [1, 5]$, zero otherwise, be the PDF of a random var. I know the expected value of $X$ is $2.75$. I was asked to find its variance. For the sake of practice I ...
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Which class will be the median class if n/2 is the cumulative frequency of a class interval?
An example problem:
When using the textbook formula, Median = L + {[(n/2)-c.f.]/f}*h, where L is the lower limit of the median class, n is the total number of observations, c.f. is the cumulative ...
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How can the Range be a measure of statistical dispersion?
Most of the sources (like 1, 2 3 and in some books like arihant) provide the definition for Statistical dispersion as " The extent to which numerical data is spread about the average value is ...
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Compare positive and negative percentages
I know that is a very, very trivial question... But I'd be super thankful for any help.
Lets say you have three values where each describes the velocity of a car.
50 kmh,
100 kmh,
150 kmh
I just want ...
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Is the sample mean absolute deviation unbiased for a normally distributed population?
Let $X_1,\ldots,X_n$ be a random sample from a normally distributed population.
Is the sample mean average deviation
$$\frac{\sum_{i=1}^n|X_i-\bar{X}|}{n}$$
an unbiased estimator of the population ...
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