Update index.Rmd

typo
line 217 was missing /10 in homework #2 item 11

chunk at lines 216 - 218 was reporting 2.92 in show answer.  added / 10 to match .explanation.

TA's and/pr staff - please re run as needed to correct slidify html
Fixing typos: it's -> its
Typo fixed

libray -> library
Merge pull request #36 from Alexander-Minyushkin/patch-1

Typo fixed
Merge pull request #35 from vatirr/master

Fixing typos: it's -> its
Merge pull request #33 from whitefishdontjump/patch-1

line 217 in Rmd was missing ' /10 ' in homework #2 item 11
Merge pull request #24 from tcarnus/patch-4

Update index.Rmd
Added some small changes to the P-values lecture
Editted the power lecture
small changes in lecture 11
Changed the PDFs for a few lectures