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Quadrant Count Ratio
The quadrant count ratio (QCR) is a measure of the association between two quantitative variables. The QCR is not commonly used in the practice of statistics; rather, it is a useful tool in statistics education because it can be used as an intermediate step in the development of Pearson's correlation coefficient. Definition and properties To calculate the QCR, the data are divided into quadrants based on the mean of the X and Y variables. The formula for calculating the QCR is then: : q=\frac, where \text is the number of observations in that quadrant and N is the total number of observations. The QCR is always between −1 and 1. Values near −1, 0, and 1 indicate strong negative association, no association, and strong positive association (as in Pearson's correlation coefficient). However, unlike Pearson's correlation coefficient the QCR may be −1 or 1 without the data exhibiting a perfect linear relationship. Example The scatterplot shows the maximum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statistics
Statistics (from German language, German: ', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model to be studied. Populations can be diverse groups of people or objects such as "all people living in a country" or "every atom composing a crystal". Statistics deals with every aspect of data, including the planning of data collection in terms of the design of statistical survey, surveys and experimental design, experiments. When census data (comprising every member of the target population) cannot be collected, statisticians collect data by developing specific experiment designs and survey sample (statistics), samples. Representative sampling assures that inferences and conclusions can reasonably extend from the sample ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statistics Education
Statistics education is the practice of teaching and learning of statistics, along with the associated scholarly research. Statistics is both a formal science and a practical theory of scientific inquiry, and both aspects are considered in statistics education. Education in statistics has similar concerns as does education in other mathematical sciences, like logic, mathematics, and computer science. At the same time, statistics is concerned with evidence-based reasoning, particularly with the analysis of data. Therefore, education in statistics has strong similarities to education in empirical disciplines like psychology and chemistry, in which education is closely tied to "hands-on" experimentation. Mathematicians and statisticians often work in a department of mathematical sciences (particularly at colleges and small universities). Statistics courses have been sometimes taught by non-statisticians, against the recommendations of some professional organizations of statisticians ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearson Product-moment Correlation Coefficient
In statistics, the Pearson correlation coefficient (PCC) is a correlation coefficient that measures linear correlation between two sets of data. It is the ratio between the covariance of two variables and the product of their standard deviations; thus, it is essentially a normalized measurement of the covariance, such that the result always has a value between −1 and 1. As with covariance itself, the measure can only reflect a linear correlation of variables, and ignores many other types of relationships or correlations. As a simple example, one would expect the age and height of a sample of children from a school to have a Pearson correlation coefficient significantly greater than 0, but less than 1 (as 1 would represent an unrealistically perfect correlation). Naming and history It was developed by Karl Pearson from a related idea introduced by Francis Galton in the 1880s, and for which the mathematical formula was derived and published by Auguste Bravais in 1844. The naming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrant (plane Geometry)
The axes of a two-dimensional Cartesian system divide the plane into four infinite regions, called quadrants, each bounded by two half-axes. The axes themselves are, in general, not part of the respective quadrants. These are often numbered from 1st to 4th and denoted by Roman numerals: I (where the signs of the (''x''; ''y'') coordinates are I (+; +), II (−; +), III (−; −), and IV (+; −). When the axes are drawn according to the mathematical custom, the numbering goes counter-clockwise starting from the upper right ("northeast") quadrant. Mnemonic In the above graphic, the words in quotation marks are a mnemonic A mnemonic device ( ), memory trick or memory device is any learning technique that aids information retention or retrieval in the human memory, often by associating the information with something that is easier to remember. It makes use of e ... for remembering which three trigonometric functions (sine, cosine, tangent and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Correlation And Dependence
In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics it usually refers to the degree to which a pair of variables are '' linearly'' related. Familiar examples of dependent phenomena include the correlation between the height of parents and their offspring, and the correlation between the price of a good and the quantity the consumers are willing to purchase, as it is depicted in the demand curve. Correlations are useful because they can indicate a predictive relationship that can be exploited in practice. For example, an electrical utility may produce less power on a mild day based on the correlation between electricity demand and weather. In this example, there is a causal relationship, because extreme weather causes people to use more electricity for heating or cooling. However, in gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QCR For Wind Speed And Pressure From Category 5 Hurricanes (1924-2007) (jitter Applied)
The Quebec Central Railway was a railway in the Canadian province of Quebec, that served the Eastern Townships region south of the St. Lawrence River. Its headquarters was in Sherbrooke. It was originally incorporated in 1869 as the Sherbrooke, Eastern Townships and Kennebec Railway, and changed its name to the Quebec Central Railway in 1875. In 1894, it built a line southward to Mégantic to connect to Canadian Pacific Railway's east-west line, the International Railway of Maine. It would eventually own around of track. In 1912, the Canadian Pacific Railway leased the Quebec Central for 99 years but continued to operate as Quebec Central Railway, including passenger service to American cities. The Quebec Central in turn leased the Massawippi Valley Railway, a short line from Lennoxville to Newport, in 1926; this allowed passenger service from Quebec City via Sherbrooke to the United States. The company operated passenger trains on several long and short routes. Its longest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Category 5 Atlantic Hurricanes
A Category 5 Atlantic hurricane is a tropical cyclone that reaches Category 5 intensity on the Saffir–Simpson hurricane wind scale, within the Atlantic Ocean to the north of the equator. They are among the strongest tropical cyclones that can form on Earth, having 1-minute sustained wind speeds of at least . The United States National Hurricane Center currently estimates that 11 tropical cyclones between 1851 (the first Atlantic hurricane season to be included in the official Atlantic Atlantic hurricane reanalysis, tropical cyclone record) and 1959 peaked as Category 5 hurricanes. However, because technologies such as satellite imagery, satellite monitoring were not available until the 1960s, some cyclones may have remained undetected. Since 1960, 31 Atlantic hurricanes have reached Category 5. Background Within the Atlantic Ocean to the north of the equator, hurricanes are officially monitored by the United States's National Hurricane Center (NHC), however, other met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guidelines For Assessment And Instruction In Statistics Education
The Guidelines for Assessment and Instruction in Statistics Education (GAISE) are a framework for statistics education in grades Pre-K–12 published by the American Statistical Association (ASA) in 2007. The foundations for this framework are the Principles and Standards for School Mathematics published by the National Council of Teachers of Mathematics (NCTM) in 2000. A second report focused on statistics education at the collegiate level, the GAISE College Report, was published in 2005. Both reports were endorsed by the ASA. Several grants awarded by the National Science Foundation explicitly reference the GAISE documents as influencing or guiding the projects, and several popular introductory statistics textbooks have cited the GAISE documents as informing their approach. The GAISE Report (pre-K–12) The GAISE document provides a two-dimensional framework, specifying four components used in statistical problem solving (formulating questions, collecting data, analyzing data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Average Absolute Deviation
The average absolute deviation (AAD) of a data set is the average of the absolute deviations from a central point. It is a summary statistic of statistical dispersion or variability. In the general form, the central point can be a mean, median, mode, or the result of any other measure of central tendency or any reference value related to the given data set. AAD includes the mean absolute deviation and the '' median absolute deviation'' (both abbreviated as MAD). Measures of dispersion Several measures of statistical dispersion are defined in terms of the absolute deviation. The term "average absolute deviation" does not uniquely identify a measure of statistical dispersion, as there are several measures that can be used to measure absolute deviations, and there are several measures of central tendency that can be used as well. Thus, to uniquely identify the absolute deviation it is necessary to specify both the measure of deviation and the measure of central tendency. The st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Deviation
In statistics, the standard deviation is a measure of the amount of variation of the values of a variable about its Expected value, mean. A low standard Deviation (statistics), deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the values are spread out over a wider range. The standard deviation is commonly used in the determination of what constitutes an outlier and what does not. Standard deviation may be abbreviated SD or std dev, and is most commonly represented in mathematical texts and equations by the lowercase Greek alphabet, Greek letter Sigma, σ (sigma), for the population standard deviation, or the Latin script, Latin letter ''s'', for the sample standard deviation. The standard deviation of a random variable, Sample (statistics), sample, statistical population, data set, or probability distribution is the square root of its variance. (For a finite population, v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statistical Ratios
Statistics (from German: ', "description of a state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model to be studied. Populations can be diverse groups of people or objects such as "all people living in a country" or "every atom composing a crystal". Statistics deals with every aspect of data, including the planning of data collection in terms of the design of surveys and experiments. When census data (comprising every member of the target population) cannot be collected, statisticians collect data by developing specific experiment designs and survey samples. Representative sampling assures that inferences and conclusions can reasonably extend from the sample to the population as a whole. An experimental study involves taking measurements of the sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
