Regression+analysis+-&nbsp;What+do+the+parameters+mean?+What+is+R-squared?+What++is+a+t-test?+How+is+it+used+in+health+care?

=**What is Regression analysis?**= Regression analysis is a method used to examine the relationship between certain variables. The goal is to find the cause-and-effect relation between these variables. A health example would be finding the cause-and-effect relation between lifestyle choices and health status. Many times the variables are differentiated between an independent variable and a dependent variable. An independent variable is one that can be changed, or the variable that causes a change in the other variable. The dependent variable is the variable affected by the independent variable. For example, we can look at the relation between health care expenditures and consumer income. Consumer income would be the independent variable since it would most likely affect one's health care expenditures, the dependent variable. Regression analysis can help us examine this type of relationship.

Answer: True
 * Question** - The independent variable causes a change in the dependent variable. True or False

=**What do the parameters mean?**= A parameter is a number that describes a characteristic of a population of scores. The symbols for different parameters are represented by letters from the Greek alphabet.

A) A sample of scores B) A population of scores C) The confidence intervals D) The relation between two means Answer: B
 * Question** - What do parameters describe?

=**What is R squared?**=

R squared is known as the coefficient of determination. It identifies the fraction of the variation in the dependent variable that is explained by the independent variable. R squared ranges from 0 to 1. The closer r squared is to zero, the less we can predict about the relationship between the variables. A score closer to 1 indicates the relationship can be predicted with less error.

A) The relationship between variables can be predicted with little error B) The relationship between variables will be hard to predict C) The independent variable is a constant D) The dependent variable is close to the population mean Answer: A
 * Question** - If R squared is close to one, what does that tell us?

=**What is a t-test?**= The t-test determines whether the means of two groups are statistically different from one another. This analysis is suitable whenever you want to compare the means of two groups. The formula for a t-test is the difference between group means divided by variability of groups. You use alpha as .05 and use a standardized table to look up the t value.

A) How close two variables are related B) The standard deviation of two groups C) Whether the means of two groups are statistically different from one another D) Whether the range of two groups are statistically diffrent from one another Answer: C
 * Question** - What does a t-test tell us?

=**How is a t-test used in health care?**= A t-test can be used in health care in several different methods. It can be used for testing the equality of means of health care costs in a paired design study. An example for a t-test in health care is a statistical analysis used for children with rhinitis. A baseline characteristics of children with or without allergic rhinitis were compared in a univariate analysis using the t-test for continuous data. A regression analysis was developed with ashtma related hospital admission during the follw up period which represets the response variable.

Santerre, Rexford E. and Nuen, Steven P. __Health Economics: Theories, Insights, and Industry Studies.__ Thompson South-Western. 2007.
 * References**

Regression Analysis. (2007). In //Wikipedia// [Web]. Wikimedia Foundation, Inc.. Retrieved April 22, 2007, from http://en.wikipedia.org/wiki/regression_analysis

Pediatrics. (2005) In Vol 115 No. 1 [Web]. Retrieved April 25, 2007, from [|http://pediatrics.aappublications.org]