Standard Error Calculators
for confidence intervals and hypothesis tests

• SE for a single mean:  No calculator is provided here.
Use the sample standard deviation divided by the square root of the sample size.
Use the summary statistic calculator with the sample data to find the sample standard deviation.    http://visualize.tlok.org/elem-stat/statistic.php

• SE for difference of means of paired data
For each pair, compute the difference.   Consider the collection of these differences as the data.  Analyze it as data on one sample mean.
• SE for the difference of sample means from independent samples   SE sample means
If necessary, use the summary statistic calculator with each set of sample data to find its sample standard deviation.    http://visualize.tlok.org/elem-stat/statistic.php
This SE calculator also gives the accurate value for the degrees of freedom.   Round to the nearest whole number to use a t-table to find probabilities in the appropriate t-distribution.

• SE for a single proportion  SE one sample proportion

• SE for the difference of sample proportions  SE sample proportions
Direct URLs:
• Difference of two sample means from two independent samples:   http://visualize.tlok.org/elem-stat/elem-stat/standard_error_diff_two_sample_means.php
• One proportion:  h http://visualize.tlok.org/elem-stat/standard_error_one_sample_proportion.php
• Difference of two sample proportions from independent samples:   http://visualize.tlok.org/elem-stat/standard_error_diff_two_sample_proportions.php

See calculators for theoretical sampling distributions

ANOVA for Difference of Means when given summarized data. http://www.tlok.org/visualize/elem-stat/anova_difference_of_means.php