Thursday, January 10, 2008

Using Excel for Statistical Analysis - Terms You Should Understand Before You Start

Excel supplies an almost infinite figure of statistical tools you can utilize to analyse data
and do meaningful statements about it. However, without apprehension the definitions of the statistical footing that Excel uses, the statistical tools offering small help.

Accordingly, this article stores some background information about Excel's statistical tools and also defines the of import statistical footing used by Excel.

Distinguishing between types of data

The scientific discipline of statistics do a cardinal differentiation between two types of information sets, population information and sample data. A population is the set of all elements of interest, while a sample is a subset of that population, drawn to do illations about the features of the population.

For example, if you desire to depict the norm figure of telecastings in American households, you can't possibly accumulate information for the full population (all American households). Instead, you must pull a sample from the population and do an estimation about the whole population based on that sample.

Unless otherwise stated, the Excel mathematical functions do a critical premise regarding the procedure used to choose the sample: they presume that the sample drawn was drawn at random, so in this case, every family would have got the same likeliness (probability) of being selected.

Tip: When making statements about a population, it is wise to verify the choice procedure used to constitute the sample. For example, if the sample were formed by randomly selecting entries from a telephone set book, this is not random choice of the sample-it excepts families with unlisted Numbers or no telephone sets and includes families with multiple telephone book entries multiple times. The families don't have got the same chance of being selected.

Elements versus Variables

When describing the information in a set, each member of the set is called an element. So if you're describing customers, each client is an element. The features of involvement in the elements are called variables. So if you're looking at yearly income, age, and sales, these would be your variables.

The experimenter pull stringss the independent variable and measurements the dependent variable after the use to see whether it experienced any effects. A random variable depicts the result of an experimentation numerically. It can take on different
values or scopes with certain probabilities. The corporate grouping of measurings obtained
for an component is called an observation.

Probability Distributions

The term chance mentions to the likeliness that an event will happen. Probabilities scope between 0 (impossible) and 1 (inevitable).

A chance statistical distribution graphically pictures how chances are distributed over distinct values or scopes of the random variable. Probability statistical distributions can take on respective shapes. For example, a uniform chance statistical statistical distribution is rectangular-it happens when there's an equal chance for every value of the random variable.

Another common chance distribution is the normal or bell curve. This happens when there's a relatively high chance of a random variable taking a certain value or scope and a symmetrically diminishing chance as you travel away from this value.

Discrete versus Continuous Variables

A distinct variable is one that can't fall to an infinite figure of digits. For example, the figure of children in a household is a distinct number, in this lawsuit a non-negative integer. A uninterrupted variable, on the other hand, can take on a value with any figure of digits. For example, you can theoretically cipher the clip it takes a individual to run a statute mile down to the least fraction of a second.

The probability, therefore, of a uninterrupted random variable taking a peculiar value is zero. Note that statistics calculated from distinct variables are uninterrupted variables. So you can state that the norm figure of children in a household is, for example, 2.3, although no household could have got 2.3 children.


An event is a aggregation of results that share a condition. For example, you could name all results in which a undertaking travels over budget or in which a batch of commodity is rejected an event.

An Excel-specific term: Logical Values

One concluding term that Excel utilizes in its statistical uses needed to be defined--the term "logical value."

In Excel, the term logical value mentions to a value (usually textual) that Excel tax returns when you come in a conditional mathematical function in a cell. A conditional mathematical function is an equation that tax returns a consequence based on whether the cell rans into the status specified.

For example, you can inquire Excel to expose the word true if a value in a cell is greater than 100 or FALSE if it is less than or equal to 100. The most common logical values are true and
FALSE, but you can make your ain logical values as well. For example, you can tell
Excel to expose the word base on balls if a value in a cell is greater than or equal to 50 or FAIL
if it is less than 50.

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