# Questions tagged [standard-error]

For basic questions in statistics involving the properties or use of standard error of the sample points present in a simple random sample.

37 questions
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### Standard error. Why does it get more accurate as N gets bigger?

I came across this quote about the Standard Error in the OpenIntro Statistics book: We required a large sample in Chapter 4 for two reasons: 1. The sampling distribution of x tends to be more ...
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### How to obtain the standard error of measurements that already have error bars?

Suppose I make three measurements: 9, 10 and 11. Let's say there is no uncertainty associated with these values because they are counts. Numbers of children in a class say. I want to know the average ...
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### Error Calculation on an Average of Errors

Recently I have done an experiment with diffraction grating. I had to calculate 'N' (number of lines per meter) from the equation sin(${\theta}$)=pN${\lambda}$. I then required an average N to use in ...
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### Variance vs. asymptotic variance of OLS estimators?

I immediately assumed that all three were true. Which one is false, and why?
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### Quickly estimating the optimal bin size for the Jackknife re-sampling method

I am trying to apply the Jackknife method to compute confidence intervals for data collected from Monte Carlo simulations. My understanding is that to counter the effect of autocorrelations I should ...
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### What is standard error (any approximation) in a variable when only Mean value and percentiles (16th and 84th) of the PDF over variable are known?

I have variable 'X' for which I know only the MEAN value along with 16th and 84th percentile of its PDF. Now this variable (X) is used in another variable calculation (let's say 'Y') for which I have ...
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### weighted means when weights don't sum up to 100%

I have a sample of tortillas from which I want to estimate the weighted mean (weighted according to market share) of sodium content in tortillas sold in the market. The way I collected this sample was ...
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### How do I calculate Cp and Cpk (Capability) on Mean and Range Charts?

so I've been working on a question involving constructing a mean and range chart with upper and lower action and warning limits, I've got the first part of the question right (I've plotted the chart ...
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### How is the Standard Deviation affected when more (bounded) random numbers are included in a sample?

If I generate random numbers between two bounds, e.g. $0$ to $100$, will the standard deviation converge to a particular value the more random numbers I generate?
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### Error of the intersection of two linear functions

I have the following linear fits of two data sets $L_1: y=(a_{1}\pm e_{1})x + (b_{1} \pm f_{1})$ $L_2: y=(a_{2}\pm e_{2})x + (b_{2} \pm f_{2})$ How do I calculate the intersection of $L_1$ and $L_2$...
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### Standard error of estimate

In order to estimate total weight of rice of 100 bags, a sample of 25 bags was weighted giving the average weight of 50 kg. If the population standard deviation is 1.5 kg, estimate the total weight of ...
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### Gap correction between two curves

I have two curves like this : I would like to be able to calculate the gap between these two curves according to the Y value. For example: In my example Y < 5, error between the two curves is ...
I'm learning how to derive standard error of the mean mathematically. I understand that standard error is the square root of the variance of the mean: $SE =\sqrt {Var((x_1+x_2+...+x_n)/n}$ And ...