A population is the entire set of units from which a sample may be drawn.

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What is the definition of population? [closed]

3.56a A college has changed its core curriculum and wants to obtain detailed feedback information from the students during each of the first 12 weeks of the coming semester. Each week, a random sample ...
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22 views

Compare variable in two independent samples

There is a hypothesis that in online health communities influential members (higher reputation) tend to post more emotional support than regular members. Emotionality of answers were determined by a ...
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sample versus population in experimental data

I am not statistically oriented, so I am hoping you might be able to help. I have a small lab setup that mimics a larger natural process (natural disaster). I have designed and completed 46 ...
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100 views

Male and Female Chess Players - Expected Discrepancies at Tails of Distributions

I'm interested in the findings of this paper from 2009: Why are (the best) women so good at chess? Participation rates and gender differences in intellectual domains This paper attempts to explain ...
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35 views

Can the population be smaller than the number of possible outcomes?

Say a random variable $X$ returns one of the values $1, 2, ..., 6$. Conceptually, does it make sense to speak of a population, where each individual element is just $1$? In other words, does the ...
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27 views

Why are estimation results sharply different from the actual population (exponential distr.)

For my work, I analyze the field failure data sometimes and make decisions accordingly. (spare parts quantity, optimum preventive replacement point, ...) I made an experiment in Excel. Using inverse ...
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42 views

How do I calculate required Sample Size to get useful confidence interval length for Bernoulli random variables?

I am pulling meta data fields from a population of 100M documents. These meta fields include things like Author Name, Author Location, Keywords, etc. Some documents have all of these meta fields, some ...
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8 views

Measure of variance between two populations

I have a set of genes, each of which composed of $10$ values, $5$ coming from population $a$ and $5$ coming from population $b$. I would like to define a measure of the variation between the two ...
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28 views

Combining info from two population coverage levels from a tolerance interval

I have some existing product data from which I've calculated a tolerance interval with a 95% confidence level with at least 95% of population covered. I would like to use this tolerance interval as a ...
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51 views

When to Use Sampling Distributions And When to Use Regular Probability Distributions [closed]

Why/When would it be better to use Sampling Distributions such as the Sampling Distribution of the Sample Mean and why/when would it be better to use a Probability Distribution (such as Beta, ...
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22 views

Statistics - (bivariate data) Planning an Inquiry

I have to conduct a statistical inquiry that is representative of a population. You have to choose from a list of situations, and my choice was to measure the weight and length of carrots. The ...
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66 views

Why do we estimate population parameters using statistic?

I had been studying statistics, I have a doubt that I couldn't find the answer of. Its related to estimating population parameters using statistic. Suppose we have a population size of 10000, we want ...
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23 views

Compare two populations by their means… t-test?

I would like to have your opinion on the best way to compare two small sized populations of 13 and 14 individuals (but I have 3 tests for each individual on my dataset, so should I use 13 and 14 or 39 ...
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76 views

Why is the standard deviation of the sample mean less than the population SD?

The sample means do not vary as much as the individual values in the population. That the sample means are less variable than the individual values in the population follows directly from the fact ...
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15 views

Probability that difference between demand for two skills in a population sample is due to chance

I am trying to measure the demand for two skills in group of companies that are hiring software developers. One skill might be e.g. Java and the other e.g. C++. If out of 100 companies, 30 report they ...
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1answer
21 views

How can I show that my sample is random and a good representation of the population?

Okay, I'm looking at a population of user reviews. I have collected a random sample of the reviews and studied the trends of the words used and sentence structure. How do I make inferences about ...
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24 views

Performing a comparison between a sample distribution and population distribution in excel or nvivo

What is a relatively easy stats test to perform in excel/nvivo that is arguably reliable and valid and a good method for comparing a sample's normal distribution with a population's normal ...
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25 views

Estimating cutoff point for sampling using bootstrapping

I'd like to determine a cutoff point for plot sampling. So far, I've sampled intensively and collected fecal pellet data for 13 forested stands. Each stand has 50 plots and the mean pellets per ...
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1answer
51 views

Estimating age distribution from first names

Is it possible to estimate an age distribution of a specific population (e.g. actors, customers, etc.) from a list of their first names? Given that data of the number of individuals grouped by birth ...
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35 views

Finite Population Variance for a Changing Population

How does the addition of one unit affect the population variance of a finite population if everything else remains unchanged? What are the conditions such that the new unit leaves the variance ...
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122 views

Estimating number of balls by successively selecting a ball and marking it

Lets say I have N balls in a bag. On my first draw, I mark the ball and replace it in the bag. On my second draw, if I pick up a marked ball I return it to the bag. If, however I pick up a ...
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31 views

Resources for when population data is available

There are hundreds if not thousands of textbooks that detail how to make population inferences from sample. However for almost all my applications at work I have the entire population of data for ...
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32 views

Mixture distribution fitting for latent variable analysis

Are there any analytic approaches to using mixture distribution fitting for latent variable analysis? I'm specifically interested in existing approaches to determining whether mixture components ...
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12 views

Heterozygosity and the Wright-Fisher model

I was reading the textbook [Probability Models for DNA Sequence Evolution][1] by Durrett. In chapter 1, he discusses the Wright ...
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25 views

Assuming the true mean

I've collected fluorescence data from some bacterial cells. Each cell has a gene in it which can be induced to fluoresce. However, even without being induced, the gene will still fluoresce a little. ...
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Measure difference in answers on survey depending on item response options

For my thesis I sent out a questionnaire that has 10 questions. I set defaults: the first seven question had the default set to the desired answer and the last three questions had the default set to ...
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54 views

Interpreting coefficient errors in regression from uncertain population

I'm working on some regressions for UK cities and have a question about how to interpret regression coefficients. In a typical regression, one would be working with data from a sample and so the ...
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49 views

Multicollinearity in a “population model”

I was talking with a colleague who told me that at the time of making logistic regression across a population did not have to worry about assumptions such as multicollinearity, because when analyzing ...
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Learning theory for search data?

Has learning theory ever been applied in practice for search log data? If so, what are some findings about generalization/learnability from this data? I'm interested in generalization about an ...
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76 views

Do you need to report the standard error of the mean when the sample is the population?

The other day, my tutor told me that whenever a mean value is reported, the standard error of the mean must be reported alongside. But surely this isn't always the case? For example, let's say we ...
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Is a sample of 1961 people out of a population of 225,000,000 a sample size that is too small? If so, why?

I am working by a set of problems on a single question in my textbook. The question explained that there was a recent survey of 1961 adults out of a population of 225,000,000 and asked me to construct ...
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Use of multiple regression for data on 20 countries representing nearly the whole population

I have operational expenditure data for 20 countries (representing 90% of the whole population) which I want to compare with other variables from the countries (e.g. GDP, Population etc). Do I still ...
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83 views

Interpolating time series

what are best ways to interpolate time series? I have three data points(1980, 1990 and 2001) and I need to interpolate them. Using R na.approx doesn't seem to be what I need since the data I need to ...
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44 views

appropriate hypothesis test for non-negative quantity

This question is intentionally written in a very abstract way, because I am interested in a generic solution, or for pointers to different possible concrete cases in different fields: I am measuring ...
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Predicting the missing data out of three values in each of the two vectors [duplicate]

I have 2 vectors of rural and urban populations of the same country. (years from 1975 to 2020) with only three values (1980, 1990 and 2001 years) in each. And I need to predict the missing data. My ...
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Is it true that values of parameters do not vary from sample to sample?

This is something I was told. However, it seems to me that parameters of a population can be functions of time, in certain situations, in which case the values of parameters could vary from sample ...
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How to identify a subset of effects as the drivers of significant differences?

Okay I will explain this as best as I can. I have an additive risk score for each of my observations (i.e. I'm putting 100 individual effects into a single variable). The means of this risk score ...
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Have population, use inferential statistics? Also, non-normal dependent variable, what to do?

Background: We are looking at parental leave in Iceland. We are particularly interested in whether the economic crisis and the resulting changes in parental leave legislation affected the time taken ...
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Augmented split plot experimental design

I planned a field experiment with different genotypes according to an augmented design (check repeated entries plus unrepeated entries). Since I am testing a segregating population, each plot split ...
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Random variables: True or False

I sometimes get confused when reading statistical definitions when they mention random variables (RV). Are they talking about a single draw? Are they talking about an estimator? To make things clear ...
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64 views

Sampling probability

Say I start off with N single cells in a sample. These are then allowed to grow untill there are x progeny from each individual cell. How many cells must I take so that I have at least one progeny ...
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218 views

How do I detect the number of distributions in a set of data?

I'm trying to detect subpopulations of data in a set of data. The problem is that the data may have more than one subpopulation and the subpopulations may not be normally distributed. For example, ...
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79 views

Finite Population Correction Factor

A simple random sample of 21 observations is drawn from a finite population of 41 individuals. If the population mean is 300 and the population variance is 7, then after applying the finite ...
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1answer
39 views

Question Regarding Statistically Significant Population Attributes

I have a problem I am trying to solve with the Chi Squared test, but I am starting to realize there are probably better methods to use, and I was looking for suggestions. Say I have two independent ...
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97 views

Spearman's rank correlation coefficient over population

I have a data set composed by 2.000.000 projects, each of them is defined by the number of active users and the size (KBs) of the project. I would like to check whether a correlation exists between ...
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26 views

Linear mixed model when interest is ONLY in population

Lets say we have 1 to 6 repeted measures over time for some (many) subjects, and the outcome is values between 0 and 23 (so we assume normal distribution). For a normal distribution the fixed effects ...
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140 views

How is this version of the pearson correlation coefficient derived?

After taking my first semester stats class I started getting more and more into statistics. Currently I've come across this version of the Pearson Correlation Coefficient. Comparing this formula to ...
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Comparing a subset of a population with the entire population?

Is it possible to compare and test actual subsets of a population to the entire actual population? That is, let's say for a baseball team we want to know which players are contributing to the team's ...
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68 views

What are the consequences of knowing (or not knowing) the range of possible answers from a test

Lets say we are interested in some unknown variable x. We poll a x at different intervals and get a set of values that x has been. However we know that if we poll x enough times we will eventually get ...
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What benefit can be gained from finding total population size

I would imagine this has been asked before but I can't find it so feel free to link if you can! Lets say I have a sample size of 100 and an unknown population size. There's a great deal I can learn ...