Which of the following is considered a sample statistic?

The sample statistic in this context is represented by x̅ (pronounced "x-bar"), which denotes the sample mean. A sample mean is calculated by summing the values of a particular sample and then dividing by the number of observations in that sample. This measure provides an estimate of the population mean (μ), but it is specific to the subset of data that has been collected.

The other terms listed represent different statistical concepts. The population mean, represented by μ, is a parameter that refers to the average of all observations in the entire population, not just a sample. The symbol σ denotes the population standard deviation and also represents a population parameter, which measures the dispersion of the entire population's values. Lastly, the letter p typically refers to a population proportion in statistics. While population parameters relate to the entire set of data, the sample mean (x̅) is derived from and specifically applies to a sample of the data, making it a sample statistic.