A certain experiment produces the data (1, 1.8), (2, 2.7), (3, 3.4), (4, 3.8), (5, 3.9). Describe the model that produces a least-squares fit of these points by a function of the form y=β1x+β2x^2. Such a function might arise, for example, as the revenue from the sale of x units of a product, when the amount offered for sale affects the price to be set for the product. Required:a. Give the design matrix, the observation vector, and the unknown parameter vector. b. Find the associated least-squares curve for the data.