probability review: syntax fixes
probability review: syntax fixes

Signed-off-by: Anand Avati <6a1810c170bd423868ce2e225ecea39d80cade0f@cs.stanford.edu>

mhzhu1/cs323-notes,kuleshov/cs228-notes,mhzhu1/cs323-notes,ermongroup/cs228-notes,kuleshov/cs228-notes