# Questions tagged [standard-deviation]

Standard deviation is the square root of the variance of a random variable, an estimator thereof, or a similar measure of the spread of a batch of data.

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### How can I separate my data into bins and plot their averages and standard deviations on a line chart? [closed]

Unfortunately, I'm kind of stuck with excel and sheets - I don't really know any programming languages. I have 3 columns of data and I'm sorting it by binning based on one of the variables and ...
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### Confidence intervals for a joint probability distribution [duplicate]

I've asked this question before but it was marked as a duplicate with this question that didn't answer my question. My question is as follows: I have a 2-D probability distribution along the lines of ...
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### What is the sd() and standard_deviation() function in R? [closed]

check <- (sd(houses$area) == standard_deviation(houses$area)) #The check variable is FALSE, which means they are not equal. My question is how do I know which ...
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### Generalizing variance to two dimensions [duplicate]

I have a 2-D probability distribution along the lines of this plot: I know how to find the confidence interval for a 1-D probability distribution (by the definition of standard deviation or the 68-95-...
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### How do you compare standard deviations?

For example, if I am a scientist evaluating 2 methods to determine blood glucose and I want to compare if one is more variable, I would take, say, 6 samples from each person (subject) and use Method A ...
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### Need help understanding Bernoulli standard deviation

I'm looking at the solution of a homework problem from a class I took many years ago and I'm not understanding how they calculated standard deviation (see question 1C here: http://datasciencelabs....
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### Determine whether an error is random?

We have two measurements of the temperature of the same object as: $T_1 = 46 \pm 2 F$ and $T_2 = 58 \pm 6 F$. Normally, the agreement between the measurements could shown to a standard deviation by ...
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### Understanding Standard Deviation for non-normally distributed data [duplicate]

On a normal distribution curve, standard deviation tells us how much data fall in each group around the mean, according to empirical law. So, for example of SD = 14 and sample mean($\bar{x}$) = 50, as ...
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### Why is variance (instead of standard deviation) the default measure of information content in principal components?

The information content of principal components is almost always expressed as a variance (e.g., in scree plots or in statements like "the first three PCs contain 95% of the total data variance"). The ...
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### How to find margin of error for 99% confidence interval for skewed distribution?

Google Sheet of data I have the value and the frequency of the data. As you can see in the data sheet, the count number is quite high, so I am not able to write out the entire list of the data (ex. 2, ...
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### How can I calculate the standard deviation by year using aweights in stata? [closed]

Without using the weights is easy with egen but I don't how to use the weights.
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### Find new mean from Normal probability

I have a problem as follows. Life of tyres normally distributed for a specific make. mean=24,000 km and sd= 2500 km. Question is: As a result of improvements in manufacture, the length of life is ...
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### How to simulate standard deviation

I would like to simulate data based on real data captured. The real data captured is 15 observations. The simulation based on the existing data is 100 observations. I have a mean and standard ...
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### Mean absolute deviation vs. standard deviation

In the text book "New Comprehensive Mathematics for O Level" by Greer (1983), I see averaged deviation calculated like this: Sum up absolute differences between single values and the mean. Then ...
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### Standard Deviation of Bernoulli trials / Bernoulli process with different probabilities

If 20 independent Bernoulli trials are carried out each with a different probability of success and therefore failure, what is the standard deviation of the result? How is this calculated?
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### Standard error of model residual SD from simulation

I'm futzing with getting the SE of model residual standard deviations from a linear regression, and keep getting narrower errors than I should - and I'd like to figure out why. The basic approach I'm ...
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### Same mean but different standard deviation, how to interpret?

Can i just assume they have the same behavior? i need some advice on how i would look at these graphs. Should I use standard deviation to analyse fluctuation or median instead of mean? or can i just ...
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### How to standardize data with low variance?

I have quarterly data of federal fund rate (test set), e.g.: ...
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### How to reconcile z-scores into a number from -1 to 1?

I'm looking at time-series data of the GDP of the economy. I'm comparing the difference in the percent change of the GDP over the past 1 months, with the past 2 months — doing this over the course of ...
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### How to reconcile z-scores into a number from -1 to 1? [duplicate]

I'm looking at time-series data of the GDP of the economy. I'm comparing the difference in the percent change of the GDP over the past 1 months, with the past 2 months — doing this over the course of ...
93 views

### Deviation Coding meaning of test statistic on grand mean (intercept)

I have a dataset with 7 factor levels none of which are a reasonable reference group, so I've chosen to set up my GLM (negative binomial) analysis using deviation coding. I've studied this question ...