At the core of biology and other sciences lies a problem-solving approach called the scientific method. 1  Make an observation. 2  Ask a question. 3  Form a hypothesis, or testable explanation. 4  Make a prediction based on the hypothesis.  Test the prediction.
Xi. Xi is the 14th letter of the Greek alphabet. It is pronounced in Modern Greek, and generally or in English. In the system of Greek numerals, it has a value of 60. Xi was derived from the Phoenician letter samekh. Xi is not to be confused with the letter chi, which gave its form to the Latin letter X.
The statistical mean can also be used to interpret statistical data. Some important properties make statistical mean very useful for measuring central tendency. Since Xi - X is the distance from a given number to the average. The numbers to the left of the mean are balanced by the numbers to the right of the mean.