An interval of random variables, depending on observed data, which, with a fixed probability, contain an unknown parameter of interest.

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1answer
11 views

Combining two estimates

The number of participants in a particular sport in the USA in 2014 was estimated by a research group at 3,000,000. This estimate came with a standard error. The number of hospitalizations associated ...
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0answers
18 views

Effect and Confidence Intervals [on hold]

I am very confused about what confidence intervals means and how they relate to effects of the medians. I sent an email to my teacher asking him more about it but he sent me this back hoping that ...
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2answers
78 views

Confidence interval for the confidence interval?

I'm studying confidence intervals, and I'm curious about how one might generate a confidence interval for the confidence interval, if that even makes sense. For example, let's say I draw simple ...
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0answers
19 views

Question about confidence interval

I got curious while I was reading about confidence interval again. Let's say I want to find out about where the person's income stands in distribution by getting confidence interval. Assuming a a 20 ...
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0answers
10 views

Estimating confidence Interval for unknown Variance, Normal distribution

I've been stuck with this question for a while: I've learnt how to use t-distribution to estimate CIs for an unknown variance, but I'm unsure how that applies to this situation. Any help would be ...
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0answers
13 views

Should I use 'sample standard deviation' for 'prediction intervals' and 'standard error of the mean' for 'confidence intervals'?

I just want to make sure I am getting this right. When I am concerned about the "result" of any particular new datapoint I should use prediction intervals not confidence intervals. When I am concerned ...
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0answers
17 views

Confidence interval of linear regression variable calculation [duplicate]

I want to be able to calculate the confidence interval from the estimated coefficient and respective standard errors. I have a linear regression model which can be summarized (in R): ...
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0answers
22 views

Distribution of the estimate inside the prediction interval while performing linear regression

I would like to clarify how to interpret the prediction interval (PI) that we get while performing linear regression. I realize that PI provides us the uncertainty in our estimate of y when X = x, ...
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1answer
42 views

Can a confidence interval be greater than 1?

I am doing a classification task and obtain an accuracy of 97.5%. Now, I calculated the confidence interval, assuming a normal distribution, at the 95% confidence level with: Accuracy +/- ...
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0answers
10 views

If you transform response time data, e.g. to generate a CI, do you transform the values back for interpretation? [duplicate]

I would like to create a CI or highest density interval for response time data. The distribution of the response times is quite skewed and I think about transforming them by LN(y). However, my ...
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0answers
31 views

confidence interval for proportion

Suppose $k$ events were observed in $n$ trials. We then have $\hat{p} = k/n$ and the standard Wald confidence interval is $$\hat{p} \pm z_{\alpha/2}\sqrt{\hat{p}(1-\hat{p})/n}$$ I wonder why the ...
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0answers
31 views

For a U-shaped distribution, how many results must I verify

--edit-- in plain English. I have a distribution with over a million points between 0 and 1 that is shaped like a U with many values falling near 0 and 1. Each point is SUPPOSED to represent a score ...
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0answers
28 views

Repeated measures, random effects structure, confidence intervals and p-values don't fit

I have repeated measures data of plant species richness with the following variables: richness (response variable measured each ...
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0answers
8 views

how to display data as a banded/area chart when data is minus? [closed]

I have a predicted dataset to display as a line with a upper and lower 95% confidence which I want to use as an area display i.e. as error bands. I initially followed this tutorial ...
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0answers
24 views

Confidence intervals and p-values of multiple factor analysis lead to different conclusions?

I have the following model: man94_141 <- glmer(richness ~ year*block + (1|tr) , family=poisson , data=datasan94_14) where richness is the number of species ...
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0answers
26 views

Predict the average stay of customers

This is my data: customers subscribing to a service and more or less regularly having activities on that service. I want to calculate an average length of stay for the customers using the service. I ...
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1answer
12 views

Finding confidence intervals in a R generated sample

Having this pob1<-rchisq(90,12) How can I estimate the expected value and variance of this sample? How do I find the 95% and 99% confidence intervals of the ...
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1answer
23 views

Confidence Interval difference in means Interpretation

I have a negative confidence interval ((-35.346,-8.570) for an independent samples t-test. I understand confidence intervals for the mean. However, I am uncertain about the interpretation of the ...
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0answers
29 views

confidence intervals for one sided test of proportions

I am interested in running A/B tests on differences in proportions and reporting the confidence intervals to convey the precision of the test. Tests would be of the form $H_{o}: p(a) \geq p(b)$ vs ...
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1answer
17 views

Can the lower/upper end of a confidence interval be interpreted separately?

A health insurance company here presents rating lists of hospitals based of their SMR (standardized mortality/morbidity ratio) values (observed/expected, i.e. the higher the worse). They use the ...
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0answers
19 views

Confidence interval for proportion differences in R [migrated]

I am looking for a quick method (without creating too many new dataframes) for the following: Imagine I have two variables: data$occupation (rows, from top to ...
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0answers
13 views

confidence score for predicted value using a regression model?

I have trained a regression model which predicts value y = f(x). I need some way to measure confidence that predicted values are true values. Specifically, in runtime, given x0, I have a predicted ...
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0answers
23 views

confidence intervals for mixed effects models with small sample size

I have several datasets, all of which have a nested structure. However, the number of groups is quite small (varies from 10-50) and the number of observations per group varies between 1-10, but most ...
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0answers
18 views

Circular statistics for showing the directional mean lies outside a specified region of a duty cycle

I'm doing an analysis to examine if my data points are clustered along a polar axis (the cycle of a repeated playback sound followed by silence). I'm interested in: Are the data points clustered ...
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1answer
31 views

Confidence interval for the geometric distribution

I have a problem proving this: Given $C(x)=[0, 3/x]$ for all $x\in\chi$, with $\chi=\Omega$ being the sample space and $P_q=Geom(q)$ being the geometric distribution. I have to show that C(x) is a ...
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0answers
13 views

Assessing significance / confidence of a crossvalidated performance measure

I have a prediction model $P$ and I use some performance measure $I$ to measure $P$'s accuracy. The distribution of $I$ is unknown (it's a custom metric, which is somehow similar to the precision ...
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0answers
8 views

Repeated measures binomial effect confidence intervals

I have a repeated measures study design with two separate conditions in a memory task where one must recognize previously seen items in a list. The conditions are concrete vs. abstract. I'd like to ...
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0answers
17 views

Average Difference of Averages

I'm looking at the gender pay gap across the UK using some data from the ONS. The data is released as mean and median gross pay by sex by local authority area. Figures for England as a whole are also ...
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0answers
44 views

95% confidence interval error bars

I'm doing a research and trying to calculate and put error bars (95% confidence) on my excel chart. However, I have trouble understanding what exactly do I have to calculate in order to present my ...
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0answers
16 views

Uniform confidence band for parametric model

Lets say we have a parametric model $\mathcal{F} = \{\text{distribution functions }F_{\theta} \;|\; \theta \in \Theta\}$ and a point estimate $\hat{\theta}$ of the corresponding parameter $\theta$ ...
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0answers
26 views

Bootstrapped confidence intervals for predicted probabilities seem too small (using glmer in lme4)

I am using logistic regression to examine factors affecting female reproductive status (0=inactive, 1=active) in a rodent species. My top model includes the fixed effect of "year" and a random ...
3
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1answer
30 views

Basic & quick question about confidence interval (novice)

I'm writing a research proposal and I need to include an estimation of what kind of sample size would be adequate. I've used a calculator, and I get the result that with a 95% confidence interval and ...
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0answers
23 views

A question about confidence intervals

Consider a population P in which each person has a trait T that indicates the frequency with which they respond to an email. Research has shown us that the average T across the population is 0.5, and ...
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0answers
26 views

Upper limit of confidence interval

The estimated median response duration was 17.5 months (range, 0.0 to 19.6; 95% confidence interval [CI], 15.8 to not reached). The above is taken from a medical study. Why was the upper limit of the ...
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1answer
37 views

Confidence Interval and P Value uncertainty for Permutation Test

I'm very new to resampling techniques. As I'm learning randomization tests right now online, there are two main questions coming to my mind: YES, it's easy and intuitive how p-value is computed with ...
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1answer
23 views

Determining 95% confidence interval of difference for proportion (Stata, or other)

I have a dataset that is looking at completeness of data entry in a survey in two populations. Variables represent each category and are allocated 1 (present) or 0 (not present). I was wondering how ...
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3answers
51 views

How to calculate and plot a 95% confidence interval in R [closed]

I am using the following R Code to calculate a "Lowess" smooth line for a data set. I then need to add a 95% confidence line that would be associated with my smooth line. ...
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1answer
33 views

Different methods, different confidence intervals

A definition of a confidence interval could be: A confidence interval for the parameter θ, with confidence level or confidence coefficient γ, is an interval with random endpoints ($u(X)$, ...
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0answers
13 views

How to report results from multinomial confidence intervals when looking for significant differences

I am comparing 4 proportions within one sample: one individual had to choose between four colours (green/red/yellow/blue). I know that significantly more individuals chose "blue" because I've ...
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0answers
36 views

Statistical testing in machine learning [closed]

I have a clarification. I am currently working as a data scientist for an IT company. I have experience in the area of NLP, ML and Big data for more than 5 years. I am from Bioinformatics background. ...
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0answers
41 views

Confidence intervals on a predicted regression line cross

I have carried out a model on some long-term data I have looking at bird arrival dates in relation to different weather conditions and have run into some problems when plotting the results. I have ...
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1answer
25 views

What are those variables in Cochran's formula

I cannot find any information about the Cochran's formula below: $$\text{Sample Size} = \frac{n}{1 + (n/\text{population})}$$ in which $n$ is equal to $Z * Z [P (1-P)/(D*D)]$ So I assume Z is the ...
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0answers
25 views

Confidence Interval for Standard Deviations from Bootstrapping in R

I'm new to bootstrapping. I would like to find the CIs for the SDs generated from a bootstrap and was wondering if I had done it correctly. ...
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0answers
14 views

How to determine the proper sample size and testing criteria range for an experiment design?

I am currently trying to design an experiment that will be testing how fast a conveyor is able to convey different size cases. The case sizes are based on 4 dimensions (LxWxH and Weight) and the case ...
5
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1answer
48 views

Does Random Forest ever compare the splitting of one node to the slitting of a **different** node?

I thought I understood how a single decision tree is constructed as part of a Random Forest : The data is split recursively until some kind of stopping conditions are met. Each split is ...
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1answer
39 views

How to combine two accuracy results?

If I am doing a machine learning experiment A and my accuracy lies in the interval of 0.8 +/-0.03 and I have a machine learning experiment B with an accuracy in the interval of 0.9 +/-0.1, how can I ...
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1answer
28 views

Standard error on an estimate derived from 2 estimated proportions - Survey data

I have survey data where I want to calculate a derived variable, based on 2 estimated proportions. (e.g., "Did you visit the web-page?" If Yes, "Did you place an order?", and I want to estimate total ...
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1answer
15 views

Small confidence interval in polynomial regression

I am studying the 7th chapter of Introduction to Statistical Learning with Applications in R (ISLR) and I don't understand why the confidence interval associated with polynomial regressions (as seen ...
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1answer
43 views

Confidence interval for variance of two samples [closed]

Considering I have two samples of 15 values of normal distributions with different parameters With only one command in R could I give a confidence interval of 95% for the proportion (ratio) of the ...
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0answers
17 views

optimum bootstrap resamples quantity

If it can be defined, what is the optimum bootstrap resamples quantity? My specific aim is to determine confidence level (CL). notes: I am not a statistician. I want to find CL for failure rates of ...