According to Chesemore (2011), statistics concerns methods based on mathematical theory and probability, which allow the user to summarize many observations in a concise way. The first documented use of statistics dates back to the 16th century; it was used by gamblers and life insurance companies. The use and development of statistical methods expanded significantly in the 20th century. The invention of the computer simplified calculations (Chesemore, 2011). In addition to learning that statistics is used more often than I thought, I learned the methods, calculations, theories behind the formulas, and requirements for each testing method. Descriptive statistics is a system used to understand large data sets. Tools include graphs, charts, and histograms. Data is plotted to determine distribution, but descriptive statistics are limited to measures of central tendency, mean, mode, median, and standard deviation (Weinclaw, 2009). Descriptive statistics are very basic; there are no tests or predictions based on testing the data. It can be used to determine whether a sample is normally distributed. The next level of statistics is inferential statistics. Inferential statistics is much more complex than descriptive statistics and is used for analysis and to make inferences based on hypothesis tests to determine the statistical significance of calculated values. Inferential statistics uses a wide range of testing procedures. The tests used depend on how the test is set up and what the user wants to find out (Weinclaw, 2009). A simple test to determine whether a sample is representative of a population is the z-test. The z test is widely used to determine whether the sample is representative of a population. After z was… halfway through the paper… disappointed that the equations needed to pick the winning powerball numbers were not included in the course. Works Cited Chesemore, D. (2011). Statistics. Salem Press Encyclopedia of Science. Retrieved from http://search.ebscohost.com.proxy-library.ashford.edu/login.aspx?direct=true&db=ers&AN=89317225&site=eds-liveTanner, D. E., & Youssef–Morgan, C. M. (2013). Statistics for managers. San Diego, CA: Bridgepoint Education, Inc.Wienclaw, R. (2009). Sociology of research beginners (online edition). Descriptive statistics (Sociology). Retrieved from http://search.ebscohost.com.proxy-library.ashford.edu/login.aspx?direct=true&db=ers&AN=89185422&site=eds-liveWienclaw, R. (2009). Sociology of research beginners (online edition). Inferential statistics. Retrieved from http://search.ebscohost.com.proxy-library.ashford.edu/login.aspx?direct=true&db=ers&AN=89185545&site=eds-live