Archive for the ‘Statistics’ Category
Thursday, December 10th, 2009
Overview of Two-Way Counting
Description
A detailed tutorial on two-way counting. Step by step tutorial including several examples of two-way counting for reference.
Overview
Two-way counting is when any expression for a given quantity are determined using two different counting approaches. Many people believe that a quadratic equation is the perfect example of two-way counting, because you find the quantity in more than one way. However, this is incorrect. Two-way counting is actually a backwards method – you have the quantity already, you just need to figure out how you could get it. This is used often in combinations and permutations, where you often already know what quantity you need to have, you just have to figure out how to get there.
Tags: binomial, combination, counting, equation, example, expression, method, permutation, quadratic, quantity, statistics, two, two-way, way
Posted in Statistics | No Comments »
Friday, November 20th, 2009
Definition of an Outlier
Description
A detailed tutorial on the definition of an outlier. Step by step tutorial including several examples of definitions of outliers for reference.
Overview
An outlier is a type of observation of statistical data. It is usually very far away from the other values in the data set, hence the name. Usually it is a number that is much smaller than the other numbers, although it could be much larger than the other numbers as well. Outliers have an equal chance of occuring in any random observation, but they are still rare. Typically when an outlier is found it means there is some sort of mistake, usually a measurement error.
Tags: chance, data, elements, equal, error, larger, measurement, mistake, numbers, observation, outlier, random, set, smaller, statistical, statistics, values
Posted in Statistics | No Comments »
Friday, November 13th, 2009
How to Find the Interquartile Range
Description
A detailed tutorial on how to find the interquartile range. Step by step tutorial including several examples of the interquartile range for reference.
Overview
The interquartile range is the range of the data between the lower or first quartile and the upper or third quartile. The interquartile range is not the whole data set – it is actually only half of the data set, although not a common half – the first and last quarter of the data is not included in the interquartile range. To find the interquartile range, all you must do is find all the quartiles, and then find the different between the upper quartile and lower quartile.
Tags: data, First, half, interquartile, lower, median, quarter, quartile, range, second, set, statistics, third, upper
Posted in Statistics | No Comments »
Friday, November 13th, 2009
Definition of a Quartile
Description
A detailed tutorial on the definition of a quartile. Step by step tutorial including several examples of the definition of a quartile for reference.
Overview
A quartile is a value that separates out statistical data. There are three quartiles, and they work together to separate data out into four different parts. The first quartile, called Q1, is the lower quartile. It is the 25th percentile of data – that is, the median of the median of the total amount of data, and the lowest count in a data set. The second quartile, called Q2, is the median of the entire data set. It is sometimes referred to as the middle value. The third quartile, called Q3, is the upper quartile. It is the 75th percentile of data – that is, the median of the median of the total amount of data, and the highest count in a data set.
Tags: 25, 50, 75, data, First, lower, median, middle, parts, percentile, Q1, Q2, Q3, quartile, second, separate, set, statistical, statistics, third, upper
Posted in Statistics | No Comments »
Thursday, November 12th, 2009
Introduction to the Margin of Error
Description
A detailed tutorial on the margin of error. Step by step tutorial including several examples of the margin of error for reference.
Overview
The margin of error is a statistic that expresses the amount of possible random sampling errors that could end up in the result of a survey. The bigger the margin of error, the less trustworthy the survey is, because it means that everything falling within the margin of error could possibly be wrong and not accurate. However, if the margin or error is small, then the survey should be very accurate.
Tags: accuracy, accurate, error, less, margin, more, random, results, right, sampling, statistics, survey, true, trustworthy, wrong
Posted in Statistics | No Comments »
Thursday, October 8th, 2009
Inverse Variation Explained
Description
A detailed tutorial on inverse variation. Step by step tutorial including several examples of inverse variation and what inverse variation is for reference.
Overview
Inverse variation states that two variables are inversely proportional if one of the variables is directly proportional with the multiplicative inverse of the other, or equivilently if their product is a constant. Inverse variation can be expressed mathematically as y = k / x, where x and y are the variables and k is a nonzero constant
Tags: constant, direct, division, inverse, k, Math, multiplicative inverse, non-zero, proportionality, reciprocal, statistics, variable, variation, x, y
Posted in Statistics | No Comments »
Thursday, October 8th, 2009
Direct Variation Explained
Description
A detailed tutorial on direct variation. Step by step tutorial including several examples of direct variation and what direct variation is for reference.
Overview
Direct variation states that given two variables x and y, y is directly proportional to x if there is a non-zero constant k such that y = k * x. The variable k is referred to as the proportionality constant or the constant of proportionality.
Tags: constant, direct, inverse, k, Math, non-zero, proportionality, statistics, variable, variation, x, y
Posted in Statistics | No Comments »
Thursday, October 8th, 2009
Combined Variation Explained
Description
A detailed tutorial on combined variation. Step by step tutorial including several examples of combined variation and what combined variation is for reference.
Overview
Combined variation refers to using both direct variation and inverse variation at the same time. Combined variation can be expressed as y = (k * x) / (z^2). Typically when both direct and inverse variation are being used, the same variable will variate directly at one point and inversely at another.
Tags: combine, combined variation, direct, inverse, k, Math, point, statistics, variable, variation, x, y, z
Posted in Statistics | No Comments »
Thursday, October 8th, 2009
Joint Variation Explained
Description
A detailed tutorial on joint variation. Step by step tutorial including several examples of joint variation and what joint variation is for reference.
Overview
Joint variation is the same as direct variation, only it is occuring for more than one variable, while direct variation only deals with one variable. Because of the similarities, joint variation is performed in the same way as direct variation, although for two variables and not one. Joint variation can be expressed as d = r * t.
Tags: d, direct, joint, joint variation, Math, one, r, similar, similarties, statistics, t, two, variable, variation
Posted in Statistics | No Comments »
Friday, September 18th, 2009
How to calculate the Average of a set of numbers?
Description
A detailed tutorial on the solving of Averages in Statistics. Step by step tutorial including several examples of how to solve Averages in Statistics for reference.
Overview
The average (also know as mean), is obtained by dividing the sum of observed values by the number of observations, n. Although data points fall above, below, or on the mean, it can be considered a good estimate for predicting subsequent data points.
Tags: arithmetic mean, average, Math, statistics
Posted in Statistics | No Comments »
