Update index.Rmd

typo
slide 17 typo: red line
slide 17 typo: red line
typos: calculus, form -> from
typos: calculus, form -> from
typos: calculus, form -> from
slide 17 typo: red line
Fixed LATEX/ R typo from Regression Models 01_03

LATEX:
\sum_{i=1^n} => \sum_{i=1}^n
\beta_1 => \hat \beta_1

R Code:
Fixed missing `/`
Added a binder pdf
Added plotly data
Update hw2.rmd, change the serial number

The serial numbers were just terrible! All of the are always "1", where is "2", however?
Merge pull request #1 from bcaffo/master

Update from first pull
Fixed expression to Variance.

Fixed expression to Variance.
  Edit Fixed expression to Variance

Fixed expression to Variance
Update hw1.md
Merge pull request #31 from Entodi/master

Fixed expression to Variance.
Merge pull request #30 from gugclo/master

Merge pull request #1 from bcaffo/master
Merge pull request #29 from jimmysun/patch-1

Update hw2.rmd, change the serial number
Merge pull request #28 from clifflu/typo_RM_01_03_patch01

Fixed LATEX/ R typo from Regression Models 01_03
Merge pull request #27 from roncoursera/master

Minor typos in 07_RegressionModels slides 01_02 and 01_03