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

learn more… | top users | synonyms

0
votes
0answers
7 views

Combining Training and Validation Sets before passing model to Test Set

I have a situation in which I am building a model to predict a physical parameter of aircrafts, let's say it's parameter Y, Given several other measured parameters of aircrafts, let's call those ...
0
votes
1answer
73 views

How much sense does median of one number make?

Median of one number = the number itself. I am calculating the median price sq ft of properties of different areas based on the different data entries I have got that include their ID, area and ...
2
votes
0answers
23 views

Runs test for a very small sample

I have six measurements taken at different time-points in an experiment, and I want to show if these measurements have a dependence on time (i.e. are they random or not). I originally presented the ...
1
vote
0answers
23 views

G test with small observed counts (~zero)

I have an experiments that counts how many events happened during a certain period of time. The experiments is repeated many times in different "runs" (I have 65 runs). Here for example the list of ...
0
votes
0answers
6 views

Minimum sample size to establish a cutoff point

I conducted a case-control study (obese and normal body weight). I want to conduct ROC curve between my variables to establish a cutoff point for vitamin depending on insulin resistance risk. Does it ...
3
votes
0answers
41 views

Is Random Forest suitable for very small data sets?

I have data set comprising 24 rows of monthly data. The features are GDP, airport arrivals, month, and a few others. The dependent variable is number of visitors to a popular tourism destination. ...
0
votes
0answers
22 views

How to compare means of two sets when one set is a subset of another and the sample sizes are not

I have two samples containing citation counts for some publications. Of those samples one is a subset of the another. That is, subset contains some exact citation counts appearing on the other sample. ...
0
votes
0answers
22 views

Which t-test to use when different sized but dependent values are in question?

I have two sets of data. At the one hand manually known correct numbers for some index values such as: ...
0
votes
0answers
20 views

Using t-test when one of the groups is only two cases?

I apply ttest2 function in MATLAB for the following data sets: x = 21 5 6 5 2 5 2 13 28 2 y= 2 5 For this comparison whether means of those sets are equal MATLAB ...
4
votes
1answer
51 views

Calculate confidence levels of a stratified sample with missing units

I'm conducting a stratified survey among health institutions; 700 units were allocated into one of the 30 strata designed to reflect the proportionality of the population. However, it's been difficult ...
1
vote
0answers
18 views

help me choose statistical analysis for my undergrad thesis [closed]

firstly, i'm sorry if i'm not very good in statistics, i just need to finish my undergraduate thesis, but my professor is very busy, that he always don't have time for me to consult my research. so ...
1
vote
2answers
107 views

How can I assess many explanatory variables with a sample small enough for in-depth qualitative (case-study) analysis?

The problem: My study is on the impact of human factor on regional development. My “subjects” are regions of the European Union. 276 exist in total under NUTS 2 classification. The idea is to use a ...
2
votes
1answer
63 views

Cross-validation on really small datasets

Let's say I have a small dataset: data <- replicate(4,rnorm(13)) I want to test the out-of-sample predictions of a regression model as a function of ...
1
vote
0answers
27 views

Test for a difference of slopes

This seems like a basic question, and I feel kind of dumb that the answer is not obvious to me. The data look like this: Four count variables, all subtypes of a class of event--car crashes (A, B, C, ...
3
votes
1answer
42 views

Find best model to predict small dataset

This is my first prediction task. I have a (very) small dataset with 59 rows and 3 features. I hope that this are not way too little samples. ...
1
vote
2answers
28 views

How to apply Wilcoxon test to small sample with NAs?

I have the following data which show some values before and after a drug. I want to test whether the drug increased the mean. I think I should use Wilcoxon test, but I don't know what to do with ...
0
votes
0answers
7 views

Suggestion on best analysis for small RCT with missing data - marginal model or RM ANOVA?

I have data from a 2-arm RCT with n=11 and n=9 in each group and three repeated observations with physiological continuous data. I have missing data for one time point in two participants. In initial ...
0
votes
0answers
24 views

Use of 3Sigma to calculate UCL & LCL

I have been given the following formula for calculating Ppk. $$ \mathrm{Ppk} = \frac{\overline x-\mathrm{LCL}}{3\sigma} ~ \text{or} ~ \frac{\mathrm{UCL}- \overline x}{3\sigma} $$ When taking ...
0
votes
1answer
64 views

Interpreting regression and $R^2$ with small $n$

I am trying to create a regression comparing resampled data from 2 sampling periods using $n=6$ samples. I have tried a few different models (e.g., linear, log-transform, and exponential), and have ...
0
votes
0answers
14 views

Null distribution of $F$-statistic in small samples with (co-)integrated time series

A fellow economist proposed an idea for dealing with significance testing in a time series model in a small sample. I doubt its validity, but I have trouble thoroughly disproving the approach. Could ...
2
votes
2answers
43 views

How confident can I be that a proportion I found in a sample is true of the population?

Out of a population of roughly 2.0 million I took a random sample using the following parameters : Confidence Level: 95% Confidence Interval: 5 The sample I got (384 items as recommended by ...
0
votes
0answers
28 views

Statistical analysis using small sample size N=11 or 15

I am analyzing firm level data to unpack the cost of producing a renewable energy technology. I have dependent variable as the production cost of the technology, independent variables are three ...
1
vote
0answers
77 views

statistical analysis for a small sample size

I would like to ask for help in choosing the correct statistical test for analyzing experimental data on small samples (4 repeats) THE EXPERIMENT: the experiment simulates development of a deposit on ...
2
votes
0answers
25 views

1 group; 4 variables; small sample - can I compare means?

I have a small sample (n = 16) that completed 4 questionnaires. I am trying to determine if any of the questionnaire mean scores are significantly higher than the others. The data isn't normally ...
1
vote
0answers
14 views

Repeated measures assistance needed

Disclaimer - I am not particularly adept at stats and have a relatively complicated design. I apologize in advance for my ignorance. Looking forward to any help I can get! Here goes... I have 2 ...
-1
votes
2answers
92 views

a question on negative mean square error

for simple random sampling, i have calculated some mean square errors of many types of ratio estimator. Well, i obtained negative mean square error. Is there a mistake? negative MSE is a normal ...
1
vote
0answers
16 views

References on how to calculate quantile of a population from a small sample

I'm a novice in statistics. I need to study a problem that basically consists in checking if the 5% quantile of a population (that can be assumed normally distributed) is above or below a given value ...
0
votes
0answers
17 views

Looking for methodology

I have a simple model as $Y=f(x_1,x_2,x_3,x_4,x_5,x_6)$. I have data for all these variables for 8 years for three companies say $A,\, B,\, C$. I want to do comparison among these three companies. A ...
0
votes
0answers
12 views

non-parametric test of frequencies nested in 4 subjects (n=4)

I have data on four individuals that were observed for a fixed period of time before and after an intervention. Data consists on the amount of times(frequency) they used certain words (related to ...
0
votes
0answers
17 views

Minimum sample for non parametric test?

Exactly how many sample to be minimum size for non parametric test? Right now i have 3 data with really2 small sample size 1. 5 pairs for wilcoxon signed rank test (pretest and postest in 1 place) 2. ...
0
votes
0answers
16 views

about degree of precision and how to select randomly a sample by using minitab or spss

I have a data set which contains dependent variable Y,and independent variable X. and Population size is N = 270 I want to choose sample from this data set with simple random sampling. What should I ...
1
vote
0answers
37 views

How to analyse a distribution with some given sample moments?

Suppose that I have n observations, $$X_1,...,X_n$$ with unknown distribution, n being small (say, between 6 and 20). If I know the first four sample moments (average, standard deviation, skewness, ...
0
votes
1answer
28 views

Hypothesis test for difference in mean for small sample where the data represents a proportion

I would like advice on which test is appropriate for the problem below. I have read numerous posts about hypothesis tests for small sample, non-parametric tests, testing differences in proportions and ...
1
vote
1answer
32 views

Small sample, likert scale as independent variable

I have a small sample of 25. The question of interested has a yes/no response (Do you own a car?) . I then have a series of questions with five point Likert Scale responses, strongly disagree to ...
0
votes
0answers
12 views

Can I compare binary outcomes averaged across matched samples with small, uneven sample sizes?

I am currently collecting data for a speech intelligibility experiment in which I am filtering sentences so that only specific spectral bands are present in the stimuli and asking subjects to report ...
0
votes
1answer
59 views

Fiting non-linear model to small data set

I want to do a small example with fitting non-linear model Here are data: x <- c(10, 15, 25) y <- c(5, 10, 15) Firstly I fit a second degree polynom: ...
0
votes
1answer
17 views

set up rejection regions given 2 populations

I need to set up rejection regions given these problems. I am very new to statistics. However, I don't know what formula to use to get those regions. One formula that I think I might use is given ...
1
vote
0answers
11 views

How do I test for separate means in a small nested data set?

My observations are grouped into 3 groups, each of these 3 groups has 2 subgroups, I have 2 observations from each subgroup. Each group appears quite well divided from each other group, and each ...
0
votes
0answers
14 views

Resampling for comparative purposes

I'm here with a question concerning resampling. My issue: I measured the stature of an individual and found him markedly tall when compared with other eight subject from the same population. However, ...
2
votes
0answers
59 views

Comparing unbalanced groups (One group has only 1 observation)

I would like to compare a continuous variable across 5 health status groups, but one of the groups has only 1 observation. Would an ANOVA/Kruskal-Wallis be valid? What can I do about the group with ...
0
votes
0answers
35 views

How do I know if my sample size is too small to take a decision?

I have been running a few advertisement campaigns for a website and I got a few signups and a smaller number of 'payment done' conversions. The campaign numbers look like these: ...
8
votes
0answers
125 views

Statistical test for one paired observation [duplicate]

In this question, @whuber writes in his reply that If you were willing to assume something about that common distribution (such as it is some Normal distribution--but without knowing or assuming ...
1
vote
1answer
59 views

Granger causality test in VAR framework: small sample

I am using Granger Causality Test in VAR framework to test the causal relationship between renewable energy consumption, gross domestic product (GDP) and carbon dioxide emissions in one country using ...
4
votes
1answer
55 views

Statistically comparing distributions with small sample sizes (for dummies)

Please assume, safely, that I know next to nothing about statistics. I do not have statistical computer programs and rely primarily on Excel, online calculators, and the good graces of smarter ...
2
votes
1answer
78 views

Is it appropriate to run Spearman on a tiny dataset?

Is it appropriate to do any statistical measures (apart from descriptive) on such a tiny dataset? Spearman's correlation coefficient for example gave a result of s = 0, rho = 1, p = 0.01667 but I'm ...
1
vote
1answer
114 views

P-Values decrease when additional significant variables added (multicollinearity?)

I am doing a study for my masters correlating two separate development indicators to election results for the incumbent government. Unfortunately, I was only only able to get 11 years worth of data ...
0
votes
0answers
8 views

Analysing small samples in different period altogether

I am trying to analyse quantitative investment funds. However, these funds does not survive for a long time. Usually they last for just two or three years before closing their business. What a friend ...
0
votes
0answers
20 views

lmer with very small sample size [duplicate]

Can lmer be performed with random slopes and intercepts when n=3?
1
vote
0answers
20 views

Training on time series data with a small number of examples

The data I have is collected from 16 smartphones - it's made up of discrete readings from various sensors (eg. accelerometer in 3 axes, intensity of sound in various frequencies etc.), at regular ...
0
votes
1answer
105 views

Increasing sample size of multivariate data with bootstrapping

I'm trying to perform variable selection methods on a small data set (approximately 100 observations with 14 predictors each). Is there any way to increase the sample size with bootstrapping? Are ...