# Tagged Questions

Refers to any statistical complication or problem due to having few data.

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### ANOVA with very uneven sample sizes— Can fit be improved through reference to a more complete dataset?

I am analyzing a set of costs for contractor services for a particular city. These data have been extremely difficult to collect due the difficulty of contacting contractors and reluctance of ...
13 views

### Applying the distribution of a large sample to estimate probability for a smaller sample

I have the sample size, mean and standard deviation for the number of births per year for my county, but I'd like to transfer that information to a smaller population within the county (ie. a school ...
22 views

### CLT in a Monte Carlo simulation, small sample

A CLT says that asymptotically the sampling distribution of the sampling mean converges to the Normal. I would like to run a Monte Carlo simulation using information on one of the model's variables ...
40 views

### How to estimate errors on a sample with very few data points

I have a very simple question to ask, but I can't figure this on my own. I have two samples: sample A with only three data points, and sample B with hundreds of points. For each sample I measure the ...
68 views

### Distribution of a sample from a normal population

If I were to collect ONE sample of size 20 from a normal population, how justified would I be in claiming that the sample is normally distributed? I'm getting a little confused since by the Central ...
210 views

### Comparing patient and control group results of a survey

I have data from a survey given to a patient group and control group. Both groups completed the same exact survey (Likert scale). One group has an n of only 5 or 6, the other n was about 15. What ...
134 views

### Compute the variance of parameter estimates given limited number of samples

I'd like to infer the variance of estimated parameter $\hat\theta$ of the density function of $f(x;\theta)$ given only a limited number of samples $X_1,\cdots,X_n$. Bootstrapping doesn't perform well ...
44 views

### data mining/predictive modelling methods for small data sets

I have a small timeseries dataset that has 30 records with 6 predictor variable and 1 response variable. I would like to regress my time series response with 6 predictor variables. I have been using ...
104 views

### Determining butterfly weight distribution

I'm a researcher studying a specific butterfly species. I've conducted an experiment where I measure the weight of this species at different locations on the earth. The data is cateogorical and ...
70 views

### Bernoulli Confidence Intervals for p very close to 0

Let's say I have the following observations from many Bernoulli distributions with different p (p1, p2, ..): Observations from Distribution 1: 10 successes, 100,000 trials, p_hat = 0.0001 ...
98 views

### Comparing means with unequal variance and very different sample sizes

I am trying to compare the means of the same variable between men and women. This is the statistics: ...
152 views

### Is randomization reliable with small samples?

Jerome Cornfield has written: One of the finest fruits of the Fisherian revolution was the idea of randomization, and statisticians who agree on few other things have at least agreed on this. ...
315 views

### Kendall's coefficient of concordance (W) for ratings with a lot of ties

I have read that Kendall W should be avoided when it comes to deal with non-rankings especially for rating scales which tend to have a lot of ties. Yet posts here seem to suggest it for ratings. As ...
30 views

### Calculate $t$ value for expanded sample using just $t$ and $n$

Imagine a sample of observations $x_1 \dots x_n$ for which a $t$-value (i.e. $\bar x/SEM$) is known. Say an additional observation of zero is added to the sample so that we have $x_1 \dots x_{n+1}$ ...
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### Fraction confidence intervals for small sample size

What is 95% confidence interval for the fraction of 5 successes out of 12 trials? Is it possible to compute confidence intervals for a sample of this size?
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### Can a small sample size cause type 1 error?

I've learnt that small sample size may lead to insufficient power and type 2 error. However, I have the feeling that small samples just may be generally unreliable and may lead to any kind of result ...
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### Path analysis, sample sizes, and alternative analysis

I am examining how English ivy affects the occurrence of a salamander species under cover objects (e.g., logs). Soil moisture is assumed to be the major factor that affect their occurrence. My ...
51 views

### Creating alert system based on standard deviation and mean: How to deal with small sample size, trends and seasonality?

I'm trying to build a daily alert system to let me know when something unusual has happened in my analytics data that might require further investigation. Right now I'm taking 7 weeks worth of data, ...
15 views

### Sample Balancing

Trying to figure out a way to balance small samples. Comparing ratios received from a survey, but sometimes I will have 25 survey responses and sometimes I will have 1. The ratios I look at might be ...
45 views

### Confidence interval for a coefficient with small N

I have a question about the confidence interval of the estimator in a multiple linear regression. Here below you can find my model: ...
120 views

### Can this be modeled by a two-sample t-test?

Here is the question: A claim is made that men from two income families earn less than men who are the sole income earners in their household: To support this claim, data from a random sample of 22 ...
104 views

### When am I allowed to make linear regression on a small sample?

I'm trying to evaluate the linear correlation between to continuous variables (% value calculated from EEG datas and the area of an anatomical region of the brain). I have a sample of 18 right now. ...
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### Best test for prediction in small sample

In the context a social sciences study, Iâ€™ve been limited to a small sample size and seek expert advice on the appropriate statistical approach to take. Iâ€™d like to go beyond the simplicity of ...
121 views

### Which test for small sample sizes?

I have got a total sample size of 12 soil samples which are splitted into 4 groups of $n=3$. A number of different variables were measured like content of organic carbon e.g. These data are ...
1k views

### Is significance of the p-value reliable with extremely small sample sizes? [duplicate]

As I'm completely new to statistics and clinical trials, I would ask you for help and clarification. Let's assume we have 2 really small samples (each of n = 2, or so) derived from two normally ...
204 views

### What can be concluded from small sample size?

I had just conducted a test where the customer wants to see a 20% improvement in perforation length from a baseline perforator. The baseline perforator has not been tested in the customer's specific ...
54 views

### Robust estimation of mean with small sample size

Working with a 2D sensor. A row consists of 4096 samples, of which there are 16 reference samples (the rest are active). The reference samples do not measure the signal, but are used to estimate the ...
117 views

### How to analyse a Likert-type scale with a very small sample size (n=15)?

Data description: I have data from questionnaire data on 15 participants (small sample). Parents rated the frequency that they rough and tumble with their child: (1) Never, (2) not very often, (3) ...
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### Small sample size (N=14) with data points measured at 6 different times

I have a study with 14 participants who received testing on Variable 1 at 2 different times (before and after the semester) to determine whether there is any change on Variable 1. Each participant ...
64 views

### Alternative to factorial logistic regression for small-n experiment.

I need help figuring out an appropriate statistical test for the following small scale experiment: 2x2 design (Treatment-Adult; Treatment-Child; Control-Adult; Control-Child) DV: binomial ...
62 views

### Unequal sample size t-test, but with group-effect

I am researching how people watch video lectures together. I have two conditions as follows: (1) 3 groups of 4 learners watch one video lecture on a shared display, but there is only one control (to ...
989 views

### Intraclass correlation coefficient interpretation

I'm having a look at the intraclass correlation coefficient in SPSS. Data: 17 participants rated two lists of 9 & 7 items from 0 to 5 (0 being unimportant and 5 being very important). All ...
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### Significance of correlation with only 11 datapoints

I am currently working on my thesis and calculating some simple correlation coefficients. I only have 11 datapoints available, but I would like to assess the statistial significance of my results. The ...
252 views

### ICC and Kappa totally disagree

Much has been written on the ICC and Kappa, but there seems to be disagreement on the best measures to consider. My purpose is to identify some measure which shows whether there was agreement between ...
58 views

### Statistics for small and unequal samples

I have a pre-test, post-test, non-equivalent groups experiment, with a sample of 62 (control and experimental groups have 31 each). My objective is to compare the effectiveness of a model of teaching ...
59 views

### Looking for agreement amongst respondents

I have a small study of 21 respondents, who rated some items from 0-5, with 0 being unimportant and 5 being very important. I know beforehand that the items are related (they are a published list of ...
219 views

### Why does increasing the number of bootstrapped cases make PLS coefficients significant?

I am running a PLS model with a low number of observations ($n=50$). While several pieces of academic work argue that this sample size is appropriate to run this type of model, I am quite confused ...
196 views

### How to estimate right-skewed distribution with very small sample size?

Suppose we have a data set consists of, say, 5 or 10 observations. The only thing we know about this set is that it came from a positive right skewed distribution. How can we fit a probability ...
126 views

### Relevance of opinion poll (500 people from 10.5 millions) [duplicate]

In local news [1] comes with information that 58% of people is for something. This information is based on option pool that ask 500 people from 10.5 million about that question. What is confidence ...
325 views

### Topic stability in topic models

I am working on a project where I want to extract some information about the content of a series of open-ended essays. In this particular project, 148 people wrote essays about a hypothetical student ...
114 views

### Good classifiers for small training sets

What are good classification methods in the case of continuous independent variables (features) and a small training set (particularly where the number of training examples is approximately equal to ...
129 views

### What is the correct way of comparing two very small groups (N = 3)?

I have 3 samples of water contamination (bacteria/L) from a lake which I want to compare to another, more "pristine" lake. So I have 6 values in total, 3 belonging to each lake: ...
269 views

### Student's t vs Mann-Whitney U for small equal samples

I have 2 groups of data to compare using a t-test, both of sample size n=5. Checking to see if the normality assumption of the test holds is difficult since the sample sizes are too small. I have ...
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### Validity of normality assumption in the case of multiple independent data sets with small sample size

Due to limitations in experimental setup, I only have small data sets with n=3. Despite the low df the difference between treated and control is large enough to generate a significant p-value. The ...