HELP PLEASE Bob's Fly catalog collected forecasts, sales, and demand data for $20$ items in one category from its previous catalog. The data is provided below in the table.For example, their forecast for the frat tem in the table was $100$ units, but it unfortunately only sold $26$ units, However, with the last item lisied, thay apld $341$ units but. could have sold tege uniti it they had ordered encugh inventory For the next catalog, they have an inm for which they forecast demand to be $380$ unite. Suppoee they will use that forecast aleng with the data in the above tabie to choose a normal distribution to model demand for this product. What standard deviation should they choose? $($Keep the answer as an integor.$)$