Why is it often impossible to know the actual value of any p

Why is it often impossible to know the actual value of any population parameter? Give an example of a population parameter that you cannot calculate, but that you can estimate.

Solution

It is often impossible to measure the mean or standard deviation of an entire population unless the population is small, or we do a nationwide census. The population mean and standard deviation are examples of population parameters--descriptive measurements of the entire population. Given the impracticality of measuring population parameters, we instead measure sample statistics--descriptive measurements of a sample. Examples of sample statistics are the sample mean, sample median, and sample standard deviation.

EXAMPLE : HEIGHT OF THE ENTIRE POPULATION OF UNITED STATES

WE CANNOT CALCULATE THAT BECAUSE THERE ARE A LOT OF PEOPLE LIVING IN USA

BUT WE CAN ESTIMATE WITH SAMPLES OF PEOPLE LIVING IN UNITED STATES