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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16 views

Figuring percentage when mean and standard deviation are given [on hold]

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: ...
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1answer
19 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 ...
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2answers
54 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 ...
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43 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
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2answers
48 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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9 views

Related to statistics graph representation

The problem is related to statistics graph representation. The question is about representing 2 datas on graph. i am unable to understand how best the data can be represented. a) Two colleges A ...
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17 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
22 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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20 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
23 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 ...
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2answers
33 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
111 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} ...
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6 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
44 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
32 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
10 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 ...
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0answers
12 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
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1answer
35 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
13 views

calculate error for a value where the value is derived from the means of 2 other values

I have 3 repeated measures for the value of VIC, so VIC has a mean and standard deviation. FAM also has 3 repeats and therefore a mean and SD. The value DCT is the mean of VIC minus the mean of FAM. ...
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0answers
41 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
21 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
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1answer
20 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
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1answer
33 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
34 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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5 views

Adding percentages with utilization and cost data

I have data on utilization and cost for medical use for a geographic area broken down by zip code. The spreadsheet has % of users, % of medications, and % of cost for each zip code, then a column that ...
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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 ...
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1answer
35 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 ...
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0answers
26 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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63 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
35 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
50 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 ...
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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
22 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
49 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 ...
1
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1answer
41 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 ...
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64 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 ...
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2answers
23 views

Commenting results in a ratio scale

Consider the following plot: Is it mathematically correct if I say blue is 50% lower than red. Because from the plot it ...
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1answer
44 views

Perform a descriptive statistical analysis and interpret your results.

The following list gives the academic rank of the 25 female faculty members at a small liberal arts college, where L represents lecturer, F represents full professor, A represents assistant professor, ...
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1answer
39 views

Descriptive statistical analysis

I have some data obtained from questionnaire. The question asks to perform a descriptive statistical analysis for the above data and hence interpret your results. What does it mean? Is it mean I have ...
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1answer
21 views

Analysing data to find the principal parameter

I have a data set $N\times M$, which contains information about motorcycles: $N$ motorcycles have been sold during some time and for each bike there is $M$ parameters regarding the sale such as price, ...
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2answers
37 views

Best way to answer average question with large range of data

I have expense data for 30+ departments. I want to figure the best way to answer the question 'what is the average expense?' The problem is that each department has a different range of data and size. ...
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2answers
27 views

Statistics and data analysis

What is meant by confidence interval in data analysis e.g. 95% confidence interval? How does p<0.05 estimate significant difference?
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0answers
20 views

Does it make sense to interpret autocorrelation and box test on 5 data points?

I am trying to see if after I trade a stock the price movements at 2, 5, 7, 10, 30 and 60 seconds after exhibit any autocorrelation. Below I have the returns from my trade price to the trade 2,5,7,10 ...
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1answer
77 views

A basic probability probem

I have question and I could not figured out how to proceed solving question: I think the probability of Success for part (a) is 0.75 and for part (b) it is 0.50. I guess this is a binomial question, ...
0
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2answers
82 views

Variance of Portfolio of Assets

The variance of a portfolio of two assets is calculated as $Var(R_P)=w_a^2\sigma_a^2+w_b^2\sigma_b^2+2w_aw_b\sigma_{ab}$, where $w_a,w_b$ are the respective weights of the two assets in the ...
5
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2answers
72 views

How can the median number of sexual partners be 6.1 and 3.6?

http://www.cdc.gov/nchs/nsfg/key_statistics/n.htm Median number of female sexual partners in lifetime, for men 25-44 years of age, 2006-2008: 6.1 Wouldn't it only be able to be x.5 or x.0?
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1answer
64 views

How does a median have a value that is a decimal which isn't exactly half of an integer if the data should consist of only integer values?

I real an article which said the average man accumulated 6.1 sexual partners while the average woman accumulates 3.6. If the statistic talked about the average, surely the numbers would be equal-so it ...
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1answer
82 views

Confidence Interval Algorithm

I am trying to write a C++ program for parameter estimation(with Confidence Interval information) of an Exponentially distributed data set. I understand that $\lambda \bar{X} \sim \Gamma(n, n)$. To ...
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2answers
47 views

Skewness in a graph of data

It seems counter-intuitive to me that a graph that is skewed right actually has more data values on the left side (and vice-versa), like in this image: I don't get how the term "skewed right" ...