Describe a method for choosing the degree of polynomial.

A linear regression of age (x) on blood lead levels (y) for men who have worked in factories that manufacture car batteries is performed. The residual plots suggest there is still a pattern remaining, and you decide to add a quadratic term (age2) for age into the model. Which of the following models is now most appropriate?   Blood lead levels = a + b21 (age) + e, e ~iid N(0, s2) Blood lead levels = a + b1 (age) + e2, e ~ iid N(0, s2) Blood lead levels = a + b1 (age) + b2 (age2) + e, e ~iid N(0, s2) Blood lead levels = a + b1 (age2) + e, e ~iid N(0, s2)

a linear regression of age (x) on blood lead levels (y) for men who have worked in factories that manufacture car batteries is perfomred.  The residual plots suggest there is still a pattern remaining, and you decide to add a quadratic term (age2) for age into the model. Which model is appropriate?

A biologist wants to predict the height of male giraffes, y, in feet, given their age, x1, in years, weight, x2, in pounds, and neck length, x3, in feet. She obtains the multiple regression equation yˆ=7.36+0.00895x1+0.000426x2+0.913x3. Predict the height of a 12-year-old giraffe that weighs 3,100 pounds and has a 7-foot-long neck, rounding to the nearest foot.

The y-intercept in a linear regression model is always relevant and of interest to investigators for every model constructed.  True  False

The regression model for the number of diseases y = 0.4x2 – 2.5x +7.2 represents the number of flu cases (y) in a town in the thousands in x years after 2010. The model shows a(n) first followed by a(n) in the number of flu cases. The year had the greatest number of cases of the flu.

The relationship between yield of maize (a type of corn), date of planting, and planting density was investigated in an article. Let the variables be defined as follows. y = maize yield (percent) x₁ planting date (days after April 20) x₂ = planting density (10,000 plants/ha) The following regression model with both quadratic terms where x3 = x₁² and x4 = x₂² provides a good description of the relationship between y and the independent variables. y=a + B₁X₁ + B₂X2 + ₂xy + B₁X₁ + e (a) If a = 21.05, ₁ = 0.654, B₂ = 0.0023, B3 = -0.0207, and ₁=0.3, what is the population regression function? (b) Use the regression function in part (a) to determine the mean yield (In percent) for a plot planted on May 4 with a density of 41,179 plants/ha. (Round your answer to two decimal places.) (c) Would the mean yield The mean yield would higher for a planting date of May 4 or May 22 (for the same density)? higher for --Select-- (d) Is it appropriate to interpret , = 0.654 as the average change in…

create a line in DESMOS with the linear regression equation: y1 - mx1 + b 2) create a second line with quadratic regression: y1 - ax1^2 + bx + c After looking at the regression in DESMOS, is the data LINEAR or QUADRATIC?

Tire pressure (psi) and mileage (mpg) were recorded for a random sample of seven cars of thesame make and model. The extended data table (left) and fit model report (right) are based on aquadratic model  Write out the estimated quadratic polynomial regression model.

True or false: The Coefficient of For two variables that have a perfect negative linear regression is one.