Regression Estimation - Power and Sample Size Calculations

Power and Sample Size Calculations

There are no generally agreed methods for relating the number of observations versus the number of independent variables in the model. One rule of thumb suggested by Good and Hardin is, where is the sample size, is the number of independent variables and is the number of observations needed to reach the desired precision if the model had only one independent variable. For example, a researcher is building a linear regression model using a dataset that contains 1000 patients . If he decides that five observations are needed to precisely define a straight line, then the maximum number of independent variables his model can support is 4, because

.

Read more about this topic:  Regression Estimation

Famous quotes containing the words power and, power, sample, size and/or calculations:

    Power and violence are opposites; where the one rules absolutely, the other is absent. Violence appears where power is in jeopardy, but left to its own course it ends in power’s disappearance.
    Hannah Arendt (1906–1975)

    But, with whatever exception, it is still true that tradition characterizes the preaching of this country; that it comes out of the memory, and not out of the soul; that it aims at what is usual, and not at what is necessary and eternal; that thus historical Christianity destroys the power of preaching, by withdrawing it from the exploration of the moral nature of man; where the sublime is, where are the resources of astonishment and power.
    Ralph Waldo Emerson (1803–1882)

    All that a city will ever allow you is an angle on it—an oblique, indirect sample of what it contains, or what passes through it; a point of view.
    Peter Conrad (b. 1948)

    Crotchless trouser allows wearer to show private parts in public. Neoprene-coated nylon pack cloth is stain resistant, water repellent and tickles thighs when walking. Tan-olive shade goes with most fetishes. Adjustable straps attach to belt for good fit and easy up-down. Pant is suitable for fast exposures as well as extended engagements. One size fits all.
    Alfred Gingold, U.S. humorist. Items From Our Catalogue, “Flasher’s Pants,” Avon Books (1982)

    He who is conversant with the supernal powers will not worship these inferior deities of the wind, waves, tide, and sunshine. But we would not disparage the importance of such calculations as we have described. They are truths in physics because they are true in ethics.
    Henry David Thoreau (1817–1862)