Mathematics Stack Exchange
Mathematics Stack Exchange

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.

Descriptive statistics is the process of using and analyzing statistics that quantitatively describe or summarize features of a collection of information.

Descriptive statistics is distinguished from in that descriptive statistics aims to summarize sampled data rather than use the data to learn about the population that the sample of data represents. Hence, descriptive statistics, unlike inferential statistics, is not developed on the basis of probability theory.

Measures used to describe a data set include—

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statistics question that only requires one answer

Consider a normally distributed set of test scores with mean $62.76$ and standard deviation $13.66$. What fraction of test scores are less than $58.75$ or greater than $86.75$? There's only one answer ... I am a bit confused on how to get the…
user112765
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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 called the dispersion of the values" But measures of…
Altair25
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Understanding Decile

I was checking a Linkedin profile and I came across this statement in the “Grade” section. It’s a little confusing. It is as follows: From the picture above, the statement in Spanish translates as: “Grade: gpa within the first decile”. Is this…
NaveganTeX
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Am I calculating the F-statistic wrongly?

So in several websites the formula for calculating f-statistic is given as: $\textrm{F-statistic} = \frac{\text{variance between sample means}}{\text{mean of variance within samples}}$ I produced two random array distributions in matlab, one…
Reza Yahyaei
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Movie Earnings and Relative Ticket Sizes

Given that movie A made 308 million and a 1 by 3 cm ticket represented A and movie B made 609 million, assuming that prices have been adjusted for inflation and ticket B is the same shape as ticket A, what would the size of ticket B be? I said if…
USC
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What is the role of "X" symbol in the box-and-whisker plot?

I just read an article that compares model forecasts by observations. I know something about box plot and I know this article achieves the $y$-axis using the subtraction of model forecast and observations, but I don't know what is this multiply…
Greensman
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Average of month ratio vs previous year

I can't figure out if it's possible to calculate the 3.125 average of monthly ratio without dividing on each month. I mean only using the year totals or year average or some aggregate of year instead of month. I tried (total of 2018)/ (total of…
grimdbx
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Statistics on life expectancies

I don't understand how to solve the last the questions of this problem. Can anybody help me with this. [The table shows the life expectancies of a child (at birth) in the United States for selected years from 1940 through 2010. (Source: U.S.…
user633979
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How to find a new average?

The average time spent on Facebook per day of 40 students in a Statistics class is 1.4 hours, while the average of the 32 students in the Calculus class across the hall is 1.9 hours. Two students from the Calculus class, who both do not use…
S.Elle
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How the formula of Combined Standard deviation works?

A question have mean and standard deviation of two groups, it ask to find out combined mean and standard deviation. I could not understand that how formula of combined standard deviation connects with general sample/population standard deviation…
Bappa
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Scatterplot with Two Regression Lines

In a scatterplot, let K denote the least-squares regression line computed with outlier A included and let L denote the least-squares regression line computed without outlier A. Which of the following must be true about the slopes of K and L? a)…
Salvador Perez
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Interpreting statistics results (Odds ratio, Confidence interval, and p-value)

I am reading a journal article and I come across this statement: Loneliness was associated with higher odds of having a mental health problem (OR: 1.17; CI: [1.13, 1.21], p = 0.000); and isolation was associated with higher odds of reporting…
bot3663369
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Defining "almost flat" mathematically

Forgive me as I am no mathematician. What would be appropriate ways of defining “almost flat” mathematically ? I have a rolling series of values that are the output of a moving average function. The goal is to identify when the trend is flat or…
Little Code
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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 also that after selecting 15 members at random we…
S. Kennedy
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