A large mall conducted a survey to estimate how much money people planned to spend during the Christmas season. The survey included 5 questions asked of randomly selected shoppers between 10 AM and 4 PM on a weekday during the month of August. The survey estimate of $250 per shopper was much lower than the actual average of $400 spent per shopper from the previous Christmas season. Do you think this result reliably indicates that sales will be lower for the upcoming Christmas? Can you identify any other reason the $250 average is so far below the previous $400 figure?