# Tagged Questions

18 views

### Calculating sampling bias when estimating population proportions

Assume a true population of size N consisting of red and blue balls, where p represents the frequency of red in the population and q represents the frequency of blue in the population. Let's say that ...
41 views

### Power calculation for case-control study

My study is assessing whether there is a correlation between two medical conditions (endometriosis) and bleeding disorders. The case participants have endometriosis and the controls do not. In both ...
71 views

### How should sampling ratios to estimate quantiles change with population size?

I want to cut my data of size N into k equal-sized bins. But I am happy with roughly equal-sized bins, with some $\varepsilon$ error. As precise quantiles of the data are computationally costly ...
139 views

### Compute the variance of parameter estimates given limited number of samples

I'd like to infer the variance of estimated parameter $\hat\theta$ of the density function of $f(x;\theta)$ given only a limited number of samples $X_1,\cdots,X_n$. Bootstrapping doesn't perform well ...
285 views

### How do I use student's-t distribution without the sample size?

Here is my question (homework obviously): A sample from a normal population produced variance 4.0. Find the size of the sample if the sample mean deviates from the population mean by no more than 2.0 ...
158 views

### Dynamic estimation of required sample size in R

I have a prospective study with no data about estimated results, that could be used to get required sample size. Data looks like this: ...
3k views

### Calculating required sample size, precision of variance estimate?

Background I have a variable with an unknown distribution. I have 500 samples, but I would like demonstrate the precision with which I can calculate variance, e.g. to argue that a sample size of 500 ...
3k views

### At least, how many times an experiment should be replicated?

Is there a recommendation on the number of times that an experiment should be replicated? As many of you know, is not always possible to make many replicas. What would be the recommended minimum? Is ...