# Tagged Questions

99 views

### Imputing standard deviations for changes from baseline

This is more of a further question on a previous topic, so my apologies if there was some way to link them that I haven't found. It is essentially the same problem as How to back-calculate change from ...
58 views

### How to include GAM response error in a Monte Carlo simulation

I am running a Monte Carlo simulation, using the results of a GAM (response) as the basis for my overall model. I would like to incorporate the error in the GAM into the final result. Since ...
450 views

### Weighted standard deviation of average

For two groups (a and b) with unequal numbers of observations (n=10 and n=30), I have given their means and sd. Calculating the weighted mean is pretty straight forward. But how can I derive the sd of ...
112 views

### Non-linear regression, plot mean, SE in R

I need to create a graph like the one below.The idea is that I have three data groups with 5 replications on the first two groups and 3 replications on the last one. I must obtain a regression curve ...
100 views

### Why do we refer to our estimates in terms of precision?

Open any statistics textbook and it will urge the need to check the 'precision of our estimates'. Take the following random variable: ...
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### Discrepancy between calculated and simulated error propagation

Just curious if anyone knows why there is a tiny but definite difference between the standard deviation as calculated by the error propagation formula and the simulation. It is only a 0.2% difference ...
113 views

### Normal distribution in R

I am trying to check what is the probability that a new observation is anomalous or not? Suppose I have the following set of observations: ...
292 views

### Standard deviation for adjusted effect size estimates

I am trying to calculate the effect size for a trait adjusted for my set of nuisance variables. My models looks like this: Trait ~ Dx + Age + Sex Where "Trait" ...
151 views

### How do I test for lower variability induced by systematic missings?

In my data, some individuals have missing data on the central predictor (father missed the intake assessment). Comparing the DVs' means for those with a missing/non-missing predictor yielded some ...
2k views

### What formula is used for standard deviation in R?

What formula is used in the standard deviation function sd in R?
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### Propagation of uncertainty/standard deviations in biological experiments

I am trying to work out how to propagate standard deviations in a biological experiment, but I have some difficulties. I have the following (semi)fictitious data originating from an image analysis ...
1k views

### How to get the difference of two numbers (standard deviation)?

I have many pairs like: A B 10 20 15.3 19.5 23 13 45 32 etc etc, I create those pairs calculating the standard deviation of many vectors (R vectors) and then ...
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### Creating an estimator with varying shock levels (SD) in R?

First time posting! I'm trying to create a logit estimator using a looping simulation, where the loop detects the number of correct prediction (my code is below). Is it possible to change the shock ...