Identify a phenomenon with a lot of variation. Is variation related to variance—if so, how? How is variance related to the standard deviation?
Standard deviation is a number that is used to show how numbers in a group are spread out compared to the average. So, if most of the numbers are close the the average the STD is low but if the numbers are farther away from the data it means that the STD is high. Standard deviation can be used in decision making when trying to see how far the data set steers from the average. It can help make more informed decisions also. One example of why knowing the spread in a data set would be important could be when buying a house. If you are looking for a 3 bed 2 bath house in a particular area it is important to know the average that houses sell for there. Then, knowing the spread of the data for houses you are looking at can help you decide if the house you are looking at is above or below the average price. This can be important to be sure you are getting a good value thus helping you make a more informed decision on the house you are going to buy.