当我们必须预测分类(或离散)结果的值时,我们使用逻辑回归。我相信我们使用线性回归来预测给定输入值的结果值。
那么,这两种方法有什么不同呢?
当我们必须预测分类(或离散)结果的值时,我们使用逻辑回归。我相信我们使用线性回归来预测给定输入值的结果值。
那么,这两种方法有什么不同呢?
当前回答
线性回归和逻辑回归的基本区别是: 线性回归用于预测一个连续的或数值,但当我们寻找预测一个值,是分类逻辑回归进入画面。
二元分类采用逻辑回归。
其他回答
基本区别:
线性回归基本上是一个回归模型,这意味着它将给出一个函数的非离散/连续输出。这个方法给出了值。例如,给定x, f(x)是多少
例如,给定一个由不同因素组成的训练集和训练后的房地产价格,我们可以提供所需的因素来确定房地产价格。
逻辑回归基本上是一种二元分类算法,这意味着这里函数的输出值是离散的。例如:对于给定的x,如果f(x)>阈值将其分类为1,否则将其分类为0。
例如,给定一组脑瘤大小作为训练数据,我们可以使用大小作为输入来确定它是良性肿瘤还是恶性肿瘤。因此这里的输出不是0就是1。
这里的函数基本上是假设函数
简单地说,线性回归是一种回归算法,它输出一个可能连续和无限的值;逻辑回归被认为是一种二进制分类器算法,它输出输入属于标签(0或1)的“概率”。
Linear regression output as probabilities It's tempting to use the linear regression output as probabilities but it's a mistake because the output can be negative, and greater than 1 whereas probability can not. As regression might actually produce probabilities that could be less than 0, or even bigger than 1, logistic regression was introduced. Source: http://gerardnico.com/wiki/data_mining/simple_logistic_regression Outcome In linear regression, the outcome (dependent variable) is continuous. It can have any one of an infinite number of possible values. In logistic regression, the outcome (dependent variable) has only a limited number of possible values. The dependent variable Logistic regression is used when the response variable is categorical in nature. For instance, yes/no, true/false, red/green/blue, 1st/2nd/3rd/4th, etc. Linear regression is used when your response variable is continuous. For instance, weight, height, number of hours, etc. Equation Linear regression gives an equation which is of the form Y = mX + C, means equation with degree 1. However, logistic regression gives an equation which is of the form Y = eX + e-X Coefficient interpretation In linear regression, the coefficient interpretation of independent variables are quite straightforward (i.e. holding all other variables constant, with a unit increase in this variable, the dependent variable is expected to increase/decrease by xxx). However, in logistic regression, depends on the family (binomial, Poisson, etc.) and link (log, logit, inverse-log, etc.) you use, the interpretation is different. Error minimization technique Linear regression uses ordinary least squares method to minimise the errors and arrive at a best possible fit, while logistic regression uses maximum likelihood method to arrive at the solution. Linear regression is usually solved by minimizing the least squares error of the model to the data, therefore large errors are penalized quadratically. Logistic regression is just the opposite. Using the logistic loss function causes large errors to be penalized to an asymptotically constant. Consider linear regression on categorical {0, 1} outcomes to see why this is a problem. If your model predicts the outcome is 38, when the truth is 1, you've lost nothing. Linear regression would try to reduce that 38, logistic wouldn't (as much)2.
逻辑回归用于预测分类输出,如是/否,低/中/高等。你基本上有2种类型的逻辑回归二元逻辑回归(是/否,批准/不批准)或多类逻辑回归(低/中/高,0-9等数字)
另一方面,线性回归是因变量(y)是连续的。 Y = mx + c是一个简单的线性回归方程(m =斜率,c是Y截距)。多元线性回归有不止一个自变量(x1,x2,x3,…)等)
非常同意以上的评论。 除此之外,还有一些不同之处
在线性回归中,残差被假设为正态分布。 在逻辑回归中,残差需要是独立的,但不是正态分布。
线性回归假设解释变量值的恒定变化导致响应变量的恒定变化。 如果响应变量的值代表概率(在逻辑回归中),则此假设不成立。
广义线性模型(GLM)不假设因变量和自变量之间存在线性关系。但在logit模型中,它假设link函数与自变量之间是线性关系。