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Stefanie🍅 · 2021年03月30日

这题是不是用计算器来算呢?

NO.PZ2020010801000009

问题如下:

Find the OLS estimators for the following data:

解释:

Doing the basic needed calculations:

β^=(XiX)(YiY)(XiX)2=20.83/8.25=2.52\widehat\beta = \frac{\sum (X_i-\overline X)(Y_i-\overline Y)}{\sum (X_i-\overline X)^2}=20.83/8.25=2.52

α^=Yβ^X=9.42.524.5=1.96\widehat\alpha = \overline Y-\widehat\beta \overline X=9.4-2.52*4.5=-1.96

Continuing to estimate the variance:

s2=1n2iϵ^i2=110244.41=5.55s^2=\frac{1}{n-2}\sum_{i} \widehat\epsilon_i ^2=\frac{1}{10-2}44.41=5.55

我用计算器按出来结果是 a=-1.921273 b=2.508061
  1. 按了两遍都是这个答案,是我按错了吗?
  2. 然后方差计算器里是🔼x的平方吗?
1 个答案

小刘_品职助教 · 2021年03月30日

同学你好,

你计算器应该是按错了,我按出来a=-1.9649;b=2.5244

这边求的方差不能通过计算器直接按出来。

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