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.

62 questions
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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 ...
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What is the best measure of error for a data set where each point is the mean of 3 quick readings?

I have an experiment that relies on measuring temperature as a function of a given condition. I change the condition, allow the temperature to stabilize as much as possible, then take 3 measurements ...
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Should I use $\sigma_x^{-2}$ or $\left(\sigma_x/x\right)^{-2}$ as my weights when fitting simulation data? My intuition tells me to use the latter.

I have simulated a set of probabilities $\{p_n\}$ by the hit-or-miss Monte Carlo method. Specifically, my program checks whether or not an $n\times n$ matrix has a certain feature or not; say that, ...
152 views

Bivariate Normal Distribution Standard Error

Data from a large population indicate that the heights of mothers and daughters in this population follow a bivariate normal distribution with correlation 0.5. Both the mothers and daughters have a ...
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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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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 can we calculate the standard error from a single sample?

Say we sample 19 dolphins for mercury levels. Say the summary of the sample is here: So the mean is 4.4 and the sample's standard deviation is 2.3 From this, why do we say the standard error (which ...
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Error term in an infinite series

Well, I've the following series: $$\frac{1}{\left(1+\epsilon\cos\left(x\right)\right)^2}=\sum_{\text{k}=0}^\infty\epsilon^\text{k}\left(1+\text{k}\right)\cos^\text{k}\left(x\right)\tag1$$ This ...
166 views

Are the statements about the confidence interval correct?

We have a 90%-confidence interval. I want to check if the following statements are correct. If double the sample, the possibility that the value that we are looking for is out of the confidence ...
345 views

Standard Error of weighted mean estimate

$X$ is a random variable with unknown distribution. A number of experiments are conducted to estimate $X$. Each experiment has a different reliability measure in estimating $X$. These $n$ experiments ...
When you divide in hypothesis testing you use the formula: $$\frac{\bar X-\mu}{s/\sqrt n}$$ but the standard error of the mean is: $$\frac s{\sqrt {n-1}}$$ Why don't you use $n-1$ when ...
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 ...