fixed a few typos
fixed a few typos

jrmontag/Data-Science-45min-Intros,DrSkippy/Data-Science-45min-Intros,jrmontag/Data-Science-45min-Intros,DrSkippy/Data-Science-45min-Intros,fionapigott/Data-Science-45min-Intros,jrmontag/Data-Science-45min-Intros,jrmontag/Data-Science-45min-Intros,fionapigott/Data-Science-45min-Intros,fionapigott/Data-Science-45min-Intros,fionapigott/Data-Science-45min-Intros,DrSkippy/Data-Science-45min-Intros,DrSkippy/Data-Science-45min-Intros,fionapigott/Data-Science-45min-Intros,jrmontag/Data-Science-45min-Intros,DrSkippy/Data-Science-45min-Intros