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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30 views

1-How my profesor reach this solution? 2-How can I use eigenvalues to compute betas?… if there is any way

this time I quite don't undertand how the profesor avoid using matrix algebra to solve this exercise. Statement: Below you can see a scatter plot of the data with the three regression lines ...
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1answer
18 views

using Negative values for a box plot (box whisker)

I am drawing a box plot for a question where the data set is the bulb life time(in hours) My 5 number summary is ...
0
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1answer
34 views

Spearmans Rank, why does it work?

Looking at spearmans rank, can someone explain how the forumula works, is their anything intuative about it?
-3
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0answers
12 views

Seasonal time series

I am working with yearly sunspot number time series, which is clearly seasonal (period of 11 years). I have tried to model it with SARIMA (so that is a seasonal time series), but the best model was a ...
1
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0answers
20 views

Directional Statistics: Computation and Interpretation of Histograms of Directional Data

Suppose $v$ is a unit random vector in $R^n$ and consider a set $V = \{v^1,v^2,\dots\}$ of samples of $v$ gained either through experiments or simulations. How do we compute and interpret the ...
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0answers
30 views

Coneptual doubts about the identically distributed random variables

Take a set of identically distributed random variables X given by $X_i = \left\{ {X_1 ,X_2 ,X_3 ,...,X_n } \right\}$, where each $X_i$ is a event like the height of people in a particular city, for ...
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1answer
8 views

Regression covariance

Suppose that we are interested in the relationship between the age of the individuals who are members of our managed-care organization and the use of physician care, as measured by visits. Suppose ...
1
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1answer
31 views

Interpreting the scatter plots of two random variables

Suppose I sample random variables A and B from normal distributions. When I do a scatter plot of these two variables I see a ...
-2
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1answer
47 views

What’s the probability the test result is positive? [closed]

A clinic offers a reliable test for a rare disease. The disease only affects one in ten thousand people. If one has the disease the test has a $98$% chance of giving a positive result, and if one does ...
8
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3answers
140 views

How should a mathematically-inclined person learn descriptive statistics?

I am interested in learning descriptive statistics. But I am completely baffled, that there seem to be no mathematically rigorous books on this subject, as far as I know at least. The Wikipedia page ...
2
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2answers
27 views

Is this histogram considered bimodal?

Is this histogram bimodal? Because when I google what a bimodal histogram looks like, I keep getting images that say histograms like these are considered bimodal. Isn't it unimodal because the ...
2
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1answer
24 views

how to compute p-value when the confidence interval is given?

Please help on this problem...This is the statement: "The immunological assay verified the presence of RuBisCO in non-treated (control) and Pb-induced leaves with average relative band intensities of ...
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0answers
46 views

Proving $\widehat{\theta}$ is an efficient estimator

Let $X\sim \Gamma(\alpha,\beta)$, $\alpha=3 \beta=\theta>0$ . The Fisher information is $I(\theta)=\frac{4}{\theta^2}$ . If $X_1,\dots,X_n$ is a random sample from this distribution show that ...
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1answer
16 views

Which is a hypergeometric distribution?

I think it is the 2nd experiment, but can someone explain why, and why isn't the other distribution a hypergeometric? Experiment 1- You are picking 100 people pout 220 million people, out of that 100 ...
4
votes
1answer
90 views

How to compute the $p$ value? and the correct explanation of the overall experiment.(Is my answer correct?)

Hello community first of all thanks for helping me with my math problems. Here I'm again with hypothesis test exercise. I want to know if I made some mistake in my answer and if someone can help me ...
0
votes
3answers
62 views

What is the difference between 10% and $\frac{1}{10}$

In a national competition , ech school had to choose 10% of students who participated in the competition . So my question is , why they didn't asked for $\frac{1}{10}$ of students who participated ? ...
2
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0answers
23 views

Figuring percentage when mean and standard deviation are given [closed]

Consider the mean combined SAT score for high school seniors is 1500, and the standard deviation is 250. Calculate the percentage of students who scored at the following levels: ...
0
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1answer
33 views

Does a larger coefficient of variation mean larger variability?

I'm reviewing right now for an exam and I've stumbled across this online reviewer. In the solution for question #2 it stated that Section B is more consistent so there is greater variability in the ...
-1
votes
2answers
61 views

Largest range of a list of five integers in which the mean, median and mode are consecutive integers

A student notices that in a list of five integers, the mean, median and mode were consecutive integers in ascending order. What is the largest range possible for these five integers and why? Please ...
1
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0answers
50 views

According to Chebyshev's rule, how many observations should lie within one and a half standard deviations of the mean?

Using the formula : $p = 1 - k^{-2}$ I calculated that $p = 1 - 1.5^{-2} = 0.56$ , which equals to $56\%$. Because I have $24$ data points I go ahead and solve the number of points is $56\%$ of ...
3
votes
2answers
49 views

How to pick the “best” line equation that fits data and passes through the origin?

I have some data shown in the image. Each symbol corresponds to a different dataset. As it can be seen the data initially behaves like a line and after some points it follows other behaviour. The ...
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0answers
25 views

maximum entropy principle: CDF of its PDF

In goodness-of-fit (gof) tests (COD, R2, X2) to discriminate PDFs, we need their CDFs. With wind speed, another PDF is by Maximum Entropy Principle or Method, of the form: $$f(v)=\exp\left\{-a_0 - ...
1
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1answer
32 views

Correlation Coefficient

I am trying to understand the following equation for Correlation Coefficient: $r = \frac{\sum_{i=1}^{n}(x_i-\bar x)(y_i-\bar y)}{\sqrt(\sum_{i=1}^{n}(x_i - \bar x)^2\sum_{i=1}^{n}(y_i-y)^2)}$ ...
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0answers
28 views

Question about confidence intervals

I have questions regarding the calculations and computations of confidence intervals basing upon the given accuracy. Here is the description from the textbook: The public health authority wants to ...
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1answer
25 views

Two questions about normal distribution and its calculation

dear community members, I got this question in my handbook for exam preparation. I was trying to calculate the output but I'm stuck with figuring out the correct value. The question is: According to ...
0
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2answers
49 views

Probability theory question about trains and it schedule

I received some question for my exam preparation, but I'm not sure about the answer. So I need some reasonable explanation of the following tasks: I. Every day Sonja arrives at the railway station ...
6
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2answers
121 views

Canonical probability distribution associated with the “harmonic mean”

Is there a canonical continuous probability distribution, the center of which is best characterized with the harmonic mean, given by $$ \mathrm{HM}(X) = n \cdot \left( \sum\limits_{k=1}^{n} ...
0
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0answers
11 views

Comparing Temperature Curves

I'm collecting a bunch of temperature data from water cool down tests and need some advice on how to best compare data from different tests. I have a test stand and as I change test variables between ...
1
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1answer
52 views

Stem and Leaf Plot for Strongly Skewed Data

How to draw a stem and leaf plot for the following large data, the data is for different EU states so there is a large difference between the data. I have to plot stem and leaf for each table i.e. ...
1
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1answer
50 views

File Compression Statistics

Statically, how is the compression of a file possible? As in, a file n bytes long can have $2^{n*8}$ (the 'times 8' part is because there are 8 bits in a byte). So, if you decrease the size then ...
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0answers
12 views

Calculate portfolio weighted averages - smoothing curve

I'll first off apologize for not knowing how to ask this question properly, but I just can't come up with the right words which is likely why I can't find an answer. I have a fairly simple portfolio ...
0
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0answers
18 views

Data Management Frequency Interval

I am given the results of 30 students for a Data Management test: $78, 81, 55, 60, 65, 86, 44, 90, 59, 81, 77, 71, 65, 39, 80, 72, 70, 64, 68, 78, 88, 73, 61, 70, 75, 96, 51, 73, 65, 67.$ The ...
0
votes
1answer
64 views

Negative Mean Square Error

For simple random sampling, I have calculated somemean square errors for ratio-type estimators such as Isaki estimator, and Prasad Singh estimator. But, Mean Square Errors i obtained are negative. ...
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0answers
51 views

Point estimate and margin of error

The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 39 for a sample of size 19 and standard ...
0
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1answer
44 views

Calculate sample variance from tallied data

How friends, I am studying Statitics on my own and I am looking for someone to promp me to understand how to approach questions of this nature. I am used to frequency tables but not this one. The ...
0
votes
1answer
22 views

How to find the median element when each element has three scores?

I know how to find the median with a list of one element but what to do with a list like this one: \begin{array}{|l|cr} & math & info & gestion\\ \hline Nelim & 0 & 4 & 0\\ ...
0
votes
1answer
24 views

“3-year average of annual 98th percentile”

I was reading the limits on particulates, in particular the allowed number of exceedences for PM2.5 in the USA and I stumbled upon this: "3-year average of annual 98th percentile" I'm not very ...
2
votes
1answer
38 views

Is not always the accumulated probability until the expected value equal to 1/2?

My problem is that doing calculations with exponential distribution, the result I get is not 1/2, and I think it should be that according to the intuitive concept of the expected value. The density ...
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2answers
35 views

Calculating a statistic of specific distributions and degrees of freedom

Firstly, what does it mean to calculate a statistic? Do they just want us to find the mean, variance, and standard deviation? For instance, if I'm asked to calculate the statistic of the Chi squared ...
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0answers
23 views

How to find the probability density function for a function's values?

If I have a function $f(x)$ with a domain $[a,b]$ and range $[c,d]$, how do I find the moments of the values the function attains in the domain? More importantly, how do I find the PDF for the ...
0
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1answer
53 views

Empirical quantile definition?

Suppose we have an order set of data $\mathcal X=\{x^{(1)},x^{(2)},...,x^{(n)}\}$ such that $x^{(1)}\le x^{(2)}\le ...\le x^{(n)}$. For some reason in my course's definition of empirical quantile, we ...
0
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0answers
28 views

Interaction information within markov chains

There is a signal $X$ for which we have $2$ noisy observations, $(Y_1,Y_2)$. These observations are individually further degraded into variables $(W_1,W_2),$ giving a Markov structure: ...
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0answers
65 views

Best way to compress a noisy observation

Say we have a discrete signal $X\in \mathcal{X}$, and a noisy observation $Y\in\mathcal{Y}$. We wish to encode $Y$ into some encoding $U$ with rate $R$. That is, $H(U)=R>0$. And we want $U$ to have ...
0
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0answers
45 views

how do we decide on which graph on statistics is good to represent the data?

Here is one of my example - I am doing some calculation based on the frame size, which is the data that can be transmitted over the medium. The output is throughput i.e. efficiency, which varies ...
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0answers
74 views

Approach to build multivariate ranking system?

I have data of various sellers on ecommerce platform. I am trying to compute seller ranking score based on various features, such as 1] Order fulfillment rates [numeric] 2] Order cancel rate ...
0
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0answers
20 views

Histogram estimator, why dividing by smoothing parameter?

In histogram estimator: $$\widehat{f}(x)=\frac{1}{nh} \sum_i^n I\left(-\frac{1}{2} \le \frac{x_i-x}{h} \le \frac{1}{2}\right)$$ why do we have to divide by smoothing parameter $h$ in first term ...
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0answers
29 views

forecasting time series with triple exponential smoothing

I am wondering how to generate seasonality values, and how to use these values to forecast from a time series. I am using the formulas found at ...
0
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1answer
52 views

Probability of Observing $N$ particles in a given volume?

I'm having an issue with a probability problem concerning solutions. Assume there is an "observational region" in a dilute solution with a volume $V$, and as solutes move across its boundary, the ...
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1answer
42 views

Do 'X' and "y' have 'zero' correlation , or can be anything between '-1' and '+1'?

let , we have bi-variate data on X and Y . Now corresponding to the value $x_0$ , y can take any value.but for all other values of x , y takes a constant value. what will be the correlation ...
0
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0answers
91 views

Parent population and Sample space

My text book proclaims that iff there is exact one element in each sample, then sample space is equivalent to parent population. And I think it's not correct. For example, let parent ...