As a simple example, consider the average daily high temperatures for two cities, one inland and one near the ocean. It is helpful to understand that the range of daily high temperatures for cities near the ocean is smaller than for cities inland. These two cities may each have the same average daily high temperature. However, the standard deviation of the daily high temperature for the coastal city will be less than that of the inland city .
Another way of seeing it is to consider sports teams. In any sport, there will be teams that are good at some things and not at others. The teams that are ranked highest will not show a lot of differences in abilities. They do well in most categories. The lower the standard deviation of their ability in each category, the more balanced and consistent they are. Teams with a higher standard deviation, however, will be less predictable. A team that is usually bad in most categories will have a low standard deviation. A team that is usually good in most categories will also have a low standard deviation. However, a team with a high standard deviation might be the type of team that scores many points (strong offense) but also lets the other team score many points (weak defense).
Trying to know ahead of time which teams will win may include looking at the standard deviations of the various team "statistics." Numbers that are different from expected can match strengths vs. weaknesses to show what reasons may be most important in knowing which team will win.
In racing, the time a driver takes to finish each lap around the track is measured. A driver with a low standard deviation of lap times is more consistent than a driver with a higher standard deviation. This information can be used to help understand how a driver can reduce the time to finish a lap.
In money, standard deviation may mean the risk that a price will go up or down (stocks, bonds, property, etc.). It can also mean the risk that a group of prices will go up or down (actively managed mutual funds, index mutual funds, or ETFs). Risk is one reason to make decisions about what to buy. Risk is a number people can use to know how much money they may earn or lose. As risk gets larger, the return on an investment can be more than expected (the "plus" standard deviation). However, an investment can also lose more money than expected (the "minus" standard deviation).
For example, a person had to choose between two stocks. Stock A over the past 20 years had an average return of 10 percent, with a standard deviation of 20 percentage points (pp). Stock B over the past 20 years had an average return of 12 percent but a higher standard deviation of 30 pp. Thinking about the risk, the person may decide that Stock A is the safer choice. Even though they may not make as much money, they probably will not lose much money either. The person may think that Stock B's 2 point higher average is not worth the additional 10 pp standard deviation (greater risk or uncertainty of the expected return).
Most math equations for standard deviation assume that the numbers are normally distributed. This means that the numbers are spread out in a certain way on both sides of the average value. The normal distribution is also called a Gaussian distribution because it was discovered by Carl Friedrich Gauss. It is often called the bell curve because the numbers spread out to make the shape of a bell on a graph.
Numbers are not normally distributed if they are grouped on one side or the other side of the average value. Numbers can be spread out and still be normally distributed. The standard deviation tells how widely the numbers are spread out.
The average (mean) and the standard deviation of a set of data are usually written together. Then a person can understand what the average number is and how widely other numbers in the group are spread out.
The way a group of numbers is spread out can also be given by the coefficient of variation (CV), which is the standard deviation divided by the average. It is a dimensionless number. Coefficient of variation is often multiplied by 100% and written as a percentage.
The term "standard deviation" was first used in writing by Karl Pearson in 1894, after he used it in lectures. It was as a replacement for earlier names for the same idea: for example, Gauss used "mean error".
53 BC
Year 53 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Messalla and Calvinus (or sometimes year 701 "Ab urbe condita"). This year has been called 53 BC since the early medieval period, when the Anno Domini calendar era became the most common way of naming years in Europe.
Harry Potter and the Deathly Hallows
Harry Potter and the Deathly Hallows is the seventh and last book in J. K. Rowling's Harry Potter series. The book was released worldwide on 21 July 2007. It became the fastest-selling book ever, with 8.3 million copies sold in the United States during the first 24 hours.
This book is about Harry Potter, the main character of the book series, going on a journey to destroy horcruxes made by the villain of the series, Voldemort.
The movie was to be released in 2010, but on 8 March 2008, it was announced that the movie will be split into two parts; part one was released on 19 November 2010 and part two was released on 15 July 2011.
In Harry potter and the Deathly hallows, Harry and Hermione visit Lily and James Potter's graves. Ron has left Harry and Hermione for a while. At the end Voldemort is finally dead once and for all. Nineteen years later Harry marries Ginny Weasley and Hermione marries Ron Weasley. They all live happily, knowing nothing can harm them now.
Boiling
Boiling is the phase change that occurs when a liquid becomes gas throughout the substance. When bubbles are formed you can tell a substance is boiling. This is not to be confused with evaporation.
The temperature at which boiling happens is called the boiling point and depends on the particular nature of the substance.
For example, water boils at around 100 °C (Celsius degrees). When water is boiling, it transforms into a vapor called water vapor.
He
He (, unstressed ) is a third-person singular pronoun used to talk about a male. "He" can be used in place of a male's name. When the name of a man has been the subject, then "he" can be used instead of that name. While "he" is the subject form, the word "him" is the object or possessive form ("see table below"). The word "he" is used for a man (or boy) where the word "she" would be used for a woman.
In the past, "he" and "him" were often used as gender-neutral pronouns. In other words, the word may have been used in a general way to refer to any person who is either male or female.
Swan River
The Swan River is an important river in Western Australia. It runs past the city of Perth and into the Indian Ocean at Fremantle.
Scheinfeld
Scheinfeld is a city in Franconia, Germany. The city has 13 districts:
The city was first mentioned in the 8th century. It lies about 40 km east of Würzburg. The settlement got town privileges in 1415.
Dirk Nowitzki
Dirk Werner Nowitzki (born June 19, 1978 in Würzburg, Germany; pronounced "durk VER-ner nah-VIT-skee") is a former German basketball player. He played for the Dallas Mavericks in the United States' National Basketball Association's (NBA).
Nowitzki started playing in the NBA in 1998. He is only the second player who was born in Germany to play in the Finals.
He is a 12-time NBA All Star. Nowitkzi won the 2006-07 NBA Most Valuable Player (MVP) Award. The Mavericks, led by Nowitzki, defeated the Miami Heat 4-2 in the 2011 NBA Finals. In addition to performing very well in general in the Finals, his 101-degree fever in Game 4 didn't stop him from scoring the winning basket to tie the series 2-2. This amazing feat is a lot like when Michael Jordan played well despite the flu in the 1997 Finals against the Utah Jazz.
Dirk's jersey number is 41.
Volkach