Questions tagged [sample-size]
This tag is very ambiguous. Use it when the question is about sample size and NONE of the following are more appropriate: [small-sample], [large-data], [power-analysis], [power], [underdetermined] or [unbalanced-classes].
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While Bayesian hypergraphs seem very interesting, won't they be even more data-hungry than Bayesian networks?
There is a part of me that is absolutely enthused that someone has developed Bayesian hypergraphs and that it has causal interpretations related to Judea Pearl's work. But with Bayesian networks ...
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5 views
Sample size for fine-tuning
I'd like to take a transformer model, e.g. BERT, that was trained on a classification task in domain A, and fine-tune it for classification in domain B. How can I estimate the number of examples I ...
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11 views
Reducing sample size given correlation within blocks
I am calculating sample sizes for about 25 groups using signal-noise calculations. However, there is a lot of noise as compared to the signal which causes each group's desired sample size to be quite ...
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7 views
Sample size estimation using GPower [closed]
If I am using a between-subjects design but with 4 treatment groups, how can I calculate the sample size using g*power, please? any help will be appreciated.
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1answer
33 views
a one sample size of median survival (time to event endpoint)
In my master thesis, I need to determine and calculate the number of cases for median time to event.
The method is according to Brookmeyer & Crowley, 1982.
My question is:
How can I determine the ...
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7 views
Sample size in Cross-sectional study
I have to calculate the sample size for a cross-sectional study conducted on children of different ages who suffered from neonatal stroke. The input variables are descriptive (weight at birth, ...
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1answer
25 views
Calculate sample size for Fisher Exact Test
I'm researching the role of sender reputation in remediating Android vulnerabilities using large-scale notification campaign. There are 2 senders with different reputations and 1 as a control (no ...
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0answers
22 views
AB Test Sample Size calculation in python [closed]
I'm trying to calculate the sample size of an ab test in python.
I saw someone answered this at:
Create an A/B Sample Size Calculator using Evan Miller's Post
Their answer is below:
...
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2answers
72 views
Lowercase $x$ vs Uppercase $X$ in statistics
There are many definitions online but they do not seem to align, or at least do not clearly correspond to, the usages I see elsewhere. For example: this website defines the difference is being $X$ ...
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2answers
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Can you actually prove if the null hypothesis is true or a type II error has occurred?
Can you actually prove if the null hypothesis is true or a type II error has occurred?
I'm new to statistics (sorry in advance!)
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1answer
42 views
Sample size confounded with factors (ANOVA)
What do you suggest doing when sample size is confounded with factors in an ANOVA?
"For example, in a two-way ANOVA, let’s say that your two independent variables (factors) are Age (young vs. old)...
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11answers
4k views
Does machine learning really need data-efficient algorithms?
Deep learning methods are often said to be very data-inefficient, requiring 100-1000 examples per class, where a human needs 1-2 to reach comparable classification accuracy.
However, modern datasets ...
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0answers
16 views
Tests for positively skewed data with large enough samples?
I'm new to statistic tests so I need a little bit of help with them. Most of my data has distribution similar to the histogram below.
As it can be seen from the histogram, the data is positively ...
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0answers
4 views
Intrabatch variabilty estimated from pooled SD and confidence intervals
I would like to calculate intrabatch variability of parameter A, which is normally distributed.
I have data of 50 batches (the same process), for each batch I have one representative sample with ...
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0answers
8 views
Derive a formula for minimum sample size to achieve desired power for a 2 sample test, for fixed significance level
Suppose you have two populations, normally distributed with means $\mu_1$ and $\mu_2$, and standard deviations $\sigma_1$ and $\sigma_2$ respectively. Test whether they have the same mean. Suppose the ...
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1answer
24 views
Verbiage on rejecting null hypothesis, Sample Size, testing
I'm new to using statistics in psychology, and I'd like to seek some guidance from this forum.
Context:
I'm running an experiment involving 5,000 participants. Half of them (2500) will receive a ...
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0answers
15 views
Non Parametric Test vs Parametric Test - Event Study - CAAR
I am currently doing an event study on M&A transactions, where I have a sample size of 280 M&A events. I have done my studies with the eventstudytools.
For all my event windows I get negative ...
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0answers
12 views
Sample size calculation for discrete choice experi
I am about to use this formula for a Discrete Choice experiment with 4 attributes each contains 3 Level. Thus, I have some question that I am cordially requesting to get an answer for :
How to fixe ...
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0answers
24 views
AIC and n - original sample size or data points?
I've got a dataset consisting of 5,000 women, who are followed for 28 days, and for each day they have an estimated survival rate. I have taken these 28 survival rates, tried different models, and are ...
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1answer
89 views
What is the sample size required to observe minimum numbers of each of two types of items?
Suppose I have a large population consisting of 1 million items. 75% of these consist of type A and 25% of type B. I need to take a sample from the population but don't know until after the sample ...
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0answers
16 views
Calculating minimum sample size for a bootstrapped a/b test
When leveraging bootstrapping for a/b testing, is it necessary to calculate a sample size required to measure a minimum detectable effect at some specified significance level? If so, how?
Context: I'...
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0answers
12 views
MANOVA: Repeated measures, within-between interaction GPower HELP
I am conducting a randomized control trial with a waitlist control group and an immediate treatment group. I have run an A priori MANOVA: repeated measures, within-between interaction G*Power analysis ...
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0answers
30 views
Type I error level vs. sample size
From Jay and Devore's Modern Mathematical Statistics, Chapter 9, problem 61 c
In most situations, would it be reasonable to
use a level .01 test in conjunction with a sample
size of 40,000? Why or ...
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1answer
43 views
What is the meaning behind a sample distribution if you only have one sample?
I'm trying to understand the meaning behind the central limit theory and the importance of CLT for inferential statistics. The problem that I encountered has to do with sample distributions.
I do ...
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1answer
21 views
When adding means of different sample sizes with known standard deviations, how can I compute the standard deviation of the combined mean?
I have three means and standard deviations that represent subscales of a factor. Each subscale has a different number of items. I am summing the three subscale means together to form a factor, and am ...
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1answer
26 views
Sample size of a vote transfer poll
A vote transfer poll asks the electorate about how they voted in the last election and how they would vote if the next election was now. With the result from both questions one could build a matrix of ...
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0answers
15 views
Sample size calculation for an estimated probability
I have a primary outcome of observing at least 1 adverse event. I would like to know the sample size for observing and adverse event of probability of 2% or greater, 5% or greater, and 10% or greater.
...
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54 views
Stop collecting data when our confidence interval is sufficiently narrow?
I am running an experiment that is unpleasant and time-consuming, so I want to minimize the number of times I have to do it. I have done a sample size calculation to determine that I need $100$ ...
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0answers
27 views
Classification evaluation: How to sample the confusion matrix for unbalanced data?
Goal and Background
My goal is to classify Twitter accounts: Account of scientist
0 = no, 1 = yes.
To this end, a scientist identification algorithm was applied
to a total of 7 Mio. accounts (no ...
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0answers
20 views
How to do low scale time series prediction? [duplicate]
I have a small time series data with 10 observations
Each observation is spaced at 20 days gap
For example, I have sales revenue from day 1, day 21, day 41, day 61 till day 221...
Now I would like to ...
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0answers
80 views
MANOVA: How to identify the most relevant dependent variables
I am facing a problem with a big number of dependent variables and relatively small sample size. Not all dependent variables might be relevant, though.
As multivariate analysis of variance (MANOVA) ...
0
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1answer
20 views
Sample size and type of hypothesis test for QC of products (frozen cattle embryos)
I have a question regarding sample size and type of hypothesis test to be used.
I am currently working on buying beef cattle embryos from overseas. The livestock department in my country is going to ...
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0answers
27 views
Hypothesis Testing and Z-test for happiness at work
I'm doing a school project and decided to look closer into this COVID-19 thing that is obviously going on at the moment. I have a hypothesis that people in teams (at work) are happier at work after ...
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22 views
Why does not the mean bootstrapped metric of an ecological bipartite network get closer to the observed metric with increased number of samples?
I wanted to construct a 95% quantile-based confidence interval using bootstrapping for the network metric of an ecological web (plant-pollinators). I realized that for some webs, despite increasing ...
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1answer
23 views
What is the minimum sample size for one-way Anova?
The research is about comparison of different education levels on self-efficacy.
The education level samples size are:
Bachelor degree , 18
Diploma, 21
Pre-U ,4
High school/secondaryschool, 17
Self-...
2
votes
1answer
71 views
CLT so we have enough burgers!
An event has 32 people. Caterers need to make burgers for these people. They expect that a person at this event might need 0, 1 or 2 burgers with probabilities 0.2, 0.55, and 0.25 respectively. We ...
2
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1answer
22 views
Sample size estimation for an Instrumental Variable Study
I'm designing pretty much a textbook instrumental variable study. Paraphrasing the actually set-up, we're planning to offer in-store discount coupons and trying to assess whether providing coupons is ...
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1answer
23 views
Sample size for two-staged cluster sampling
I have a question about the R-package samplesize4surveys.
I want to calculate sample size for tests of difference in proportions in a two-step clustered sampling ...
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1answer
25 views
Minimising the sample size of a binomial distrubution
Say a survey is taken where the options are yes and no. We can take the values to correspond to $1$ and $0,$ if this is done for each person, $n$ (our sample size) Bernoulli distributions are created ...
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1answer
23 views
Reconciling sample size calculations using Cochran's formula and Wald test
This is quite a basic question but I could not find a clear answer elsewhere.
If we wish to draw a simple random sample to determine the estimated proportion of an attribute in the population, given a ...
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1answer
22 views
Does sample size have measurement unit?
Sample size (n) refers to the number of participants or observations included in a study through which statistical inferences for the whole population are made. Can sample size have measurement unit, ...
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0answers
36 views
Order statistics and sample size
How do I estimate the odds of the highest value elements of samples from two populations, A and B, exceeding a threshold value, where the same size of A is larger than that of B? Even if A and B have ...
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0answers
17 views
Sample Size - GPower options in F tests, ANOVA: Repeated measures, within factors
I'm trying to determine sample size and found that the "Options" in G*Power 3.1.9.7 changes the effect size (seems to automatically convert this and provides the same results, first two ...
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0answers
21 views
How to choose the adequate sample width?
I'm conducting some experiments. My aim is to measure the time needed by a board to do some stuff (it is not relevant for my question but, if needed, ask in the comment). The point is that the ...
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0answers
10 views
What is the consideration to choose cohen d value (0.2, 0.5, or 0.8) to determine the sample size?
I am currently designing the proper sample size in my research about the correlation of two variables. I am using G*Power and using Exact test family and correlation: bivariate normal model ...
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1answer
81 views
A/B test sample size formula confusion
I was trying to understand the math behind some commonly used calculators and formulas for A/B tests and it seems that there might be some variations. Ideally, I would like to understand how each of ...
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2answers
71 views
Sample size needed for a survey with multiple questions
I want to make a survey with several questions and conclude those results for the whole population. For example, I want to estimate the following questions for my 1 million population : "do you ...
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1answer
65 views
How to calculate sample size and prove non-inferiority/equivalence between two risk prediction models
I am in need of determining the appropriate sample size to allocate to a test set in order to prove equivalence/non-inferiority of two prediction models.
My model is a deep learning based model (using ...
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0answers
36 views
Accurately estimating the parameters for mixture of geometric distributions
Say we have an i.i.d. sample from a mixture of Geometric distributions:
$$
\begin{cases}
Geo(p_1) &w.p. \pi_1\\
Geo(p_2) &w.p. 1- \pi_1
\end{cases}
$$
Call the parameter set ${\theta}=(\pi_1,...
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0answers
23 views
What is a good location equivalence test for comparison of small and large samples?
I have two one-dimensional samples, one is small (like 2 values) and another of a larger size (several dozens). I want to estimate the probability that the two samples are drawn from different ...
