Sam's total revenue from pilot training classes equaled $90,400. Sam's implicit costs for this year are equal to

Proportion of us adults who own a cell phone. in a survey of 1006 us adults in 2014, 90% said they had a cell phone.1

True or false: a fitted model with more predictors will necessarily have a lower training set error than a model with fewer predictors.

Simon, aged 10, is invited to a classmate's birthday party at an exclusive ski resort on march 15th. the day will include 4 hours of snowboarding, lunch and birthday cake. simon's mother checks a box on the invitation that says "yes, we will attend" and returns it to the classmate's address. unfortunately, they later don't attend the party when simon comes down with the flu. on march 17th, simon's mother receives an invoice in the mail from simon's classmate for $35 that says, "party no-show fee." can simon's classmate collect the fee?