One of the biggest issues of the 21 st century, yet to capture widespread attention, is rapidly changing expert projections of the global population over the coming decades. Not so long ago, ...

The United States is growing older. The median age in this country is rising, according to the Census Bureau. The median is now almost 39 years old, meaning that half the population is below that age ...

What is a one sample t test? The t test is a commonly used hypothesis test in statistics that allows us to compare the mean value of a group of sampled data with some hypothesized value, usually a ...

A t-test for a population mean tests the population mean against a hypothesized value. It is appropriate when the population standard deviation is unknown and the sample size is small. This applet ...