Quartiles Quartiles are the values that divide a list of numbers into quarters. First put the list of numbers in order Then cut the list into four equal parts The Quartiles are at the "cuts" Like this: Example: 5, 8, 4, 4, 6, 3, 8 Put them in order: 3, 4, 4, 5, 6, 8, 8 Cut the list into quarters: And the result is: Quartile 1 (Q1) = 4 Quartile 2 (Q2), which is also the Median, = 5 Quartile 3 (Q3) = 8 Sometimes a "cut" is between two numbers ... the Quartile is the average of the two numbers. Example: 1, 3, 3, 4, 5, 6, 6, 7, 8, 8 The numbers are already in order In this case Quartile 2 is half way between 5 and 6: Quartile 1 (Q1) = 3 Quartile 2 (Q2) = 5.5 Quartile 3 (Q3) = 7 Interquartile Range The "Interquartile Range" is from Q1 to Q3: To calculate it just subtract Quartile 1 from Quartile 3, like this: Example: The Interquartile Range is: Box and Whisker Plot You can show all the important values in a "Box and Whisker Plot", like this: A final example covering everything: Put them in order: Cut it into quarters:
Site inter-établissements - Cookies et vie privée Utilisation des cookies Qu'est-ce qu'un cookie ?Un « cookie » est un fichier texte susceptible d'être déposé sur votre terminal à l'occasion de votre visite de notre site. Il a pour but de collecter des informations anonymes relatives à votre navigation et de vous adresser des contenus adaptés. Plus d'information sur les cookies sur le site de la CNIL. Conformément aux dispositions de la loi du 6 janvier 1978 relative aux fichiers, à l'informatique et aux libertés, vous disposez d'un droit d'accès, de rectification et d'opposition aux données personnelles vous concernant. Standard Deviation The standard deviation of a probability distribution is defined as the square root of the variance where is the mean, is the second raw moment, and denotes the expectation value of . is therefore equal to the second central moment (i.e., moment about the mean), The square root of the sample variance of a set of values is the sample standard deviation The sample standard deviation distribution is a slightly complicated, though well-studied and well-understood, function. However, consistent with widespread inconsistent and ambiguous terminology, the square root of the bias-corrected variance is sometimes also known as the standard deviation, of a list of data is implemented as StandardDeviation[list]. Physical scientists often use the term root-mean-square as a synonym for standard deviation when they refer to the square root of the mean squared deviation of a quantity from a given baseline. , and To find the standard deviation range corresponding to a given confidence interval, solve (5) for , giving
Normal Distribution Data can be "distributed" (spread out) in different ways. But there are many cases where the data tends to be around a central value with no bias left or right, and it gets close to a "Normal Distribution" like this: A Normal Distribution The "Bell Curve" is a Normal Distribution. Many things closely follow a Normal Distribution: heights of people size of things produced by machines errors in measurements blood pressure marks on a test We say the data is "normally distributed". Quincunx Standard Deviations The Standard Deviation is a measure of how spread out numbers are (read that page for details on how to calculate it). When you calculate the standard deviation of your data, you will find that (generally): Example: 95% of students at school are between 1.1m and 1.7m tall. Assuming this data is normally distributed can you calculate the mean and standard deviation? The mean is halfway between 1.1m and 1.7m: Mean = (1.1m + 1.7m) / 2 = 1.4m Standard Scores How far is 1.85 from the mean?
Se former Lettres lycée - Les outils TICE pour les Lettres et les LCA Les incontournables en Lettres 1. Le pad est le nom anglais donné aux espaces collaboratifs.Ces espaces permettent d'écrire à plusieurs mains et favorisent un vrai travail de groupe, qui peut se poursuivre à distance. Framapad (version française) et pirate pad (version anglaise) sont des éditeurs de textes collaboratifs qui permettent de réaliser un travail à la fois collectif et simultané en salle multimédia. 2. L'application sur internet : TagxedoUn tutoriel de l'académie de Grenoble : tutoriel tagxedo 3. Il permet de créer très simplement des livrets multimédias et interactifs, seul ou avec des élèves. 4. 5. 6. A noter que ces incontournables sont aujourd'hui intégrés aux ENT (etherpad, baladodiffusion, moodle ...) Pour aller plus loin : répertoire des outils numériques pour les Lettres Le répertoire des outils 2.0 en français (portail Skoden) réunit l'ensemble des logiciels et applications qui peuvent intéresser les lettres. Le guide des indipensables du Web 2015 : Français
Correlation When two sets of data are strongly linked together we say they have a High Correlation. The word Correlation is made of Co- (meaning "together"), and Relation Correlation is Positive when the values increase together, and Correlation is Negative when one value decreases as the other increases Like this: Correlation can have a value: 1 is a perfect positive correlation 0 is no correlation (the values don't seem linked at all) -1 is a perfect negative correlation The value shows how good the correlation is (not how steep the line is), and if it is positive or negative. Example: Ice Cream Sales The local ice cream shop keeps track of how much ice cream they sell versus the temperature on that day, here are their figures for the last 12 days: And here is the same data as a Scatter Plot: We can easily see that warmer weather leads to more sales, the relationship is good but not perfect. In fact the correlation is 0.9575 ... see at the end how I calculated it. Correlation Is Not Good at Curves Where:
Standing at the Wavefront of Scientific Discovery: A leadup to the Nobel Prize in Physics Across the globe, a handful of individuals will be woken from sleep or stopped in their tracks while crossing a busy street as they are interrupted from their otherwise ordinary day with a phone call from the Nobel Prize committee. Over the next week, the Royal Swedish Academy of Sciences will announce this year's Nobel Prize winners. Awarded in accordance with the will of Alfred Nobel, the prizes will go "to those who, during the preceding year, shall have conferred the greatest benefit to mankind," through their advances in the disciplines of medicine or physiology, physics, chemistry, literature, and peace. For those of us not expecting the free trip to Sweden, the Nobels are a great opportunity to catch up on the science behind some of the top inventions and discoveries contending for the prize in physics. Quantum Entanglement and Nonlocality The latter half of the 20th century has witnessed the experimental verification of some of the mind-bending theories of the quantum mechanics.
Calculating the mean from a frequency table It is easy to calculate the Mean: Add up all the numbers, then divide by how many numbers there are. Example 1: What is the Mean of these numbers? Add the numbers: 6 + 11 + 7 = 24 Divide by how many numbers (there are 3 numbers): 24 ÷ 3 = 8 The Mean is 8 But sometimes you won't have a simple list of numbers, you might have a frequency table like this (the "frequency" says how often they occur): (it says that score 1 occurred 2 times, score 2 occurred 5 times, etc) You could list all the numbers like this: But rather than do lots of adds (like 3+3+3+3) it is often easier to use multiplication: And rather than count how many numbers there are, we can add up the frequencies: So let's calculate: And that is how to calculate the mean from a frequency table! Here is another example: Example: Parking Spaces per House in Hampton Street Isabella went up and down the street to find out how many parking spaces each house had. What is the mean number of Parking Spaces? Answer: Notation (where f is frequency)