Questions tagged [small-sample]

Refers to statistical complications or problems due to having few data. If your question is about a small sample relative to the number of variables, please use the [underdetermined] tag instead.

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2
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1answer
46 views

How to visualize 10-fold cross-validation results?

I want to visually compare the 10-fold cross-validation results of two models. (Note that the data are paired, as both models are fit to the same folds and tested against the same held out fold on ...
2
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1answer
57 views
+50

Estimating moments of annual return distribution

I am interested in estimating moments of annual return distributions of indices with limited historical data. I.e. equity/fixed income indices which have only 10-20 years of daily data available. The ...
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1answer
29 views

Statistical test for single sample vs empirical distribution?

I have a sort of strange problem, where my sample is difficult to obtain, but the population distribution is easy to obtain. Specifically, I have obtained a single observation. I would like to know ...
2
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1answer
23 views

How to quantify the impact of small volume samples

I'm trying to quantify the impact of sample volume and variability on the propensity for false negatives, but I'm having trouble making a connection between the idea and the math to quantify it. An ...
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0answers
14 views

Decrease hyparam 'C' in SVM classifier

In a hypothetical case where I have a small dataset and I break it into train/test. Then I tune the hyperparams doing k-fold on the train set and choose the 'C' hyperparameter that maximizes my AUC on ...
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0answers
36 views

Small number of positive cases in a large data set [closed]

I am not professional user of R (but interested in) and I have data set of 900 patients and only 19 of them were positive in a analysed variable (disease progression), and I have many parameters for ...
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0answers
16 views

Artificially increase sample size with VAE samples

I want to apply a statistic (KL) on (moderate) high dimensional data and therefore need a lot of data. As its not given, I want to create additional samples that are alike the original data but not ...
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0answers
9 views

Use boostrap to compute confidence interval of KL statistic

I have two sample distributions p and q. samples in p are maybe identically distributed to samples in q or not. this is the task. samples within one group are iid. p and q have the same cardinality. ...
1
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1answer
35 views

What is the values of sample size when saying small or large sample?

A basic question in statistics. When it is said that: Fisher's exact test is employed when sample sizes are small. The normal distribution can be used as an approximation to the binomial ...
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0answers
11 views

Can pooled standard deviation be used to determine sample size?

I would like to use Minitab statistical software to determine a minimum sample size for precision (repeatability) testing. From casual observation, we know our allowable error is much wider than the ...
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0answers
20 views

sigma is unknown, so it must be estimated by using sigma approximately equals (1/4) * (range) [duplicate]

Suppose you want to estimate the average age of all Boeing 737-300 airplanes now in active domestic U.S. service. You want to be 95% confident, and you want your estimate to be within one year of the ...
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0answers
23 views

Is it problematic when very few samples are $\ne 0$ for the interaction term?

I am analyzing a data with 200 thousand observations and I am estimating $Y_{ist} = Group_{ist} + Treatment_{ist} + \beta Group_{ist} \times Treatment_{ist} +\epsilon$ where $\beta$ is the ...
0
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1answer
14 views

When to use RANSAC?

Does it make sense to use RANSAC-type algorithms (RANSAC, MSAC, MLESAC, etc.) for small data sets (20-30 points)? On the one hand, all the points need to be accounted for and this can be done with ...
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0answers
15 views

Hypothesis test for testing statistical difference of two samples of 4 instances each

I have been asked to perform a statistical analysis of two very small samples (just 4 instances per group) and I want to assess whether they come from the same or different distributions. So we have ...
1
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1answer
28 views

Method to determine if sample size increase would result in null hypothesis rejection

Say that I have a dataset of 100 observations, I build a model to predict a dependent variable given independent variables, and the p-value is such that the null hypothesis cannot be rejected. Is ...
1
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1answer
47 views

Interpreting a significant correlation in a small sample

I found a correlation between two variables: Variable A is dichotomous, with values 1 and 2 (for yes/no) Variable B is continous (score, 0 - 50) They correlated with each other. However, my sample ...
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0answers
13 views

Random variables with known ratios

I have $n$ samples with $m$ random variables in each: $\{x_{i\alpha}|i=1..n, \alpha=1..m\}$. The variables are expected to obey known ratios (they are fractions of an unknown quantity), e.g. $x_{\...
2
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0answers
41 views

Case-Control study with 1:N matching and a continuous outcome variable

I'm interested to compare cases with controls on a continuous outcome variable. The cases are people with a certain disease, while the controls are matched on various criteria (age, sex, etc) thought ...
0
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0answers
19 views

Deviation from fit and undersampling of data: can I correlate the two?

I am dealing with data measuring the subjects' response delay after a stimulus is presented on a screen. Most subjects respond within 1 second and the dataset is well fit by a linear equation in this ...
1
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2answers
59 views

Zero Frequency and Small Sample Size

I have a situation where the skeletons from one of three archaeological sites do not display a bone condition called periostitis that is found at the other two. The relevant statistics are: ...
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0answers
17 views

Is there a nonparametric regression to analyze repeated measures

I get involved in a study with only 40 subjects, and each subject has repeated measures at 6 months, 12 months, and 24 months. Originally I supposed that the total sample size 40x3 = 120 should be ...
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0answers
25 views

Comparing boxplots with different sample size

Let's suppose somebody did an experimented to measure how high a plant can grow on different soils. The experiment has been repeated different times for the different soils, with some soils having e.g....
1
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1answer
36 views

I have two small samples of different populations. How do I test if the population variance (not mean) of one is smaller than the other?

So, samples a and b; for simplicity's sake suppose that the sample variance of a is less than b, and my null hypothesis is that the population variance of A is not greater than that of B. I am not ...
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0answers
15 views

Inference from small sample size with aggregated country data

I have a data set with country aggregate patient data for yearly total number of diseases, treatments provided by health services, and some other covariates for two countries over 10 years. The ...
2
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0answers
14 views

Estimating proportion

In the context of an ecological study, I am trying to estimate the proportion of a certain mode of transmission on total incident cases of a disease (i.e. "x % of the incident cases transmitted by Z"),...
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0answers
22 views

comparing distributions of pearson correlations with very small sample size

I have a couple hundred 4-sample measurements for two different conditions. If I calculate Pearson correlation for these pairs of measurements to generate a distribution from all of my paired ...
1
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1answer
82 views

book recommendation: statistics (time-series) for small samples [closed]

I was hoping someone could recommend a good book on statistical methods for time-series on small data samples. We are really looking to do some forecasting/extrapolation given 13 years of previous ...
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0answers
21 views

How to pick the model that minimizes the mean absolute error when the amount of observations is small

I am given a data set with 1 target variable and 12 features for only 18 observations. My goal is to build a model that has the smallest expected prediction error. I am allowed to use simple methods ...
1
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2answers
70 views

Small Sample Size and NOT normally distributed

Say $n_1=4$ and $n_2 = 5$. If I want to compare the mean, should I: Standardize the data (i.e., using the scale() function in R), then perform t-test. This is because t-test required the data to be ...
1
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1answer
23 views

Adding a covariate to a meta-regression with low sample size

In an meta-regression I am working on an interesting question has come up. I am are running a meta-regression with 32 study sites. I have four theoretically motivated covariates I want to examine. ...
4
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3answers
2k views

Neural network vs regression in a small sample

I have a small numeric dataset with 20 observations and 30 variables. I want to approximate Y as a function of the rest 29 Xs(x1,x2,x3...x29). I've tested: neural network (NN) with 1 hidden layer ...
1
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2answers
45 views

In a small sample set, what constitutes unbalanced? I want to do a t-test

I want to do a t-test on my data set. However, my data set is very small and unbalanced (e.g. 10 in one group and 6 in another). Each group has a normal distribution and equal variance according to ...
0
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1answer
30 views

How to address large sampling units but small sample sizes?

I've got data from eight one-hectare tropical forest plots, with all trees greater than a certain size measured and identified within them. These plots are different forest ages with two replicates ...
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0answers
17 views

Calculate proper number of elements in a sample

Suppose that I own several convenience stores across the U.S. and I want to infer the share of market for different brands by just analyzing their sell behavior in my stores (ex. I might infer that ...
2
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1answer
63 views

Statistical analysis with very small sample size, 5 independent variables and 2 (possibly) dependent variables

I have a small sample size of 6 (they're conservation projects). They have been scored for 5 project design parameters (5 independent variables). And they have been scored for 2 desired project ...
4
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1answer
207 views

Predict time series with a very small dataset

I have a problem with a dataset where I do not exactly know how to work with. Here it is: ...
0
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2answers
43 views

How to choose at what sample size standard deviation becomes reliable for my purposes?

I'm calculating standard deviation for a normally distributed variable. I'm receiving data samples online, and I've noticed that right after the start (for a small sample size) standard deviation is ...
4
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3answers
171 views

Does it make sense to do Cross Validation with a Small Sample?

I have a set with 16 samples and 250 predictors. I'm being asked to perform CV on the set. In the examples I've looked at, you create training and testing subsets. The sample size seems quite small to ...
1
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1answer
19 views

Group comparison for small sample with repeated measured data

I have very small dataset. When I conducted rank sum test between the groups (A vs B; A vs C), I found no significant results, but just trends level difference. Is there any alternative statistical ...
0
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0answers
21 views

Small sample size with very skewed right response [duplicate]

I have a dataset of 300 observations with 7 predictor variables with 1 continuous response variable. The response is strongly skewed to the right and there are no significant correlations among any ...
1
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1answer
48 views

Rule of thumb Overfit in a MLP or is it possible with N = 135

I want to say ahead that I highly appreciate any Literature recommendation (Book, blogg, ...) besides ESL and ISL. My Question: Is it possible to train a 3 layer multilayer perceptron (mlp) in a ...
5
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2answers
127 views

What apples do worms prefer? [closed]

I'm confused with some practical statistical problem, for which I have limited data and don't understand how to start with the problem. If anybody can point how such problems are (traditionally) ...
2
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0answers
242 views

GANs for non image data

I'm looking to narrow down the subject for my bachelor thesis: I am currently working on a project, that only offers a small dataset and there will be no more data incoming for now. What I'm trying to ...
2
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1answer
134 views

intuition behind SD+

so i was reading statistics by Freedman and in the section where he describes the t-test he goes on to explain why we would use the SD+ instead of the regular SD to calculate the S.E with the sample ...
0
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0answers
13 views

Comparing 1 group and multiple variables

Hi Guys my sample is 10 female hockey players and my project aim is assessing the effect exercise has on VOMS ( visual ocular motor screening test) for concussion. The test is a seated test comprised ...
0
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1answer
30 views

Small sample size ANOVA

I am working with monthly results of some variables, and I would linke to compare weather 6 years are statistically different or not, so my saple size per group (year) is bounded by 12. I ran Shapiro ...
0
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0answers
23 views

Detecting significant trend / non-stationarity in small sample time series

I am trying to detect whether there is a significant change in plankton size over time. As I understand, this is referred to as stationarity testing in time series analysis. Unfortunately, my time ...
0
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0answers
47 views

SVM on small dataset: no difference in loss value after feature selection and small lambda

I am running an SVM on a very small dataset of 56 items, 20 features and 4 classes. I want to know which features are the most important for classification, and how they interact (no future real ...
0
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0answers
11 views

Minimal number of obs for BEKK(1,1) and DCC GARCH

For my thesis I am using a rolling regression to estimate the BEKK(1,1) and DCC GARCH parameters and their corresponding confidence intervals. There is literature on the minimal number of ...
2
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2answers
80 views

What is the best way to get the most accurate results with this small dataset?

This is my first question here, I apologize if this is the wrong place or my formatting is not correct. My experience with machine learning and data science in general is a graduate level survey ...

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