3. (20 pts) Suppose that we have 4 observations for 3 variables y , x\, X2...
3. (20 pts) Suppose that we have 4 observations for 3 variables y,I, 2 and consider a problem of regressing y on two (qualitative) variables r, 2. Data: 22 obs no. y (Income) 2 (Management Status) I (Gender) 1 None Female 2 None Male Yes Female Yes Male 4 To handle the qualitative variables r, 12, we define dummy variables 1, 22 as for 1, 22= Yes Male for 1, 219 22 -1. for 22= None for 1= Female -1,...
Suppose we have the following values for a dependent variable, Y, and three independent variables, X1, X2, and X3. The variable X3 is a dummy variable where 1 = male and 2 = female: X1 X2 X3 Y 0 40 1 30 0 50 0 10 2 20 0 40 2 50 1 50 4 90 0 60 4 60 0 70 4 70 1 80 4 40 1 90 6 40 0 70 6 50 1 90 8 80 ...
For observations {Y, X;}=1, recall that for the model Y = 0 + Box: +e the OLS estimator for {00, Bo}, the minimizer of E. (Y: - a - 3x), is . (X.-X) (Y-Y) and a-Y-3X. - (Xi - x) When the equation (1) is the true data generating process, {X}- are non-stochastic, and {e} are random variables with B (ei) = 0, B(?) = 0, and Ele;e;) = 0 for any i, j = 1,2,...,n and i j, we...
Question 4 1 pts Suppose that we are given the following model, where x1 and 2 are quantitative: E(y) = Bo + B121 + B2X2 + B3 21 22 What is the slope for x1 when x2 - 0? OBB ОВ,
2.4 We have defined the simple linear regression model to be y =B1 + B2x+e. Suppose however that we knew, for a fact, that ßı = 0. (a) What does the linear regression model look like, algebraically, if ßı = 0? (b) What does the linear regression model look like, graphically, if ßı = 0? (c) If Bi=0 the least squares "sum of squares" function becomes S(R2) = Gyi - B2x;)?. Using the data, x 1 2 3 4 5...
3. Suppose we have a data set with five predictors, X1 = GPA, X2 = IQ, X3 = Gender (1 for Female and 0 for Male), X4 = Interaction between GPA and IQ, and X5 = Interaction between GPA and Gender. The response is starting salary after graduation in thousands of dollars). Suppose we use least squares to fit the model, and get Bo = 50, 8 = 20, B2 = 0.07, B3 = 35, B4 = 0.01, B5 =...
4. Testing for significance Aa Aa Consider a multiple regression model of the dependent variable y on independent variables x1, x2, X3, and x4: Using data with n = 60 observations for each of the variables, a student obtains the following estimated regression equation for the model given: 0.04 + 0.28X1 + 0.84X2-0.06x3 + 0.14x4 y She would like to conduct significance tests for a multiple regression relationship. She uses the F test to determine whether a significant relationship exists...
Suppose of the first drug is need to compare the effects of two drugs each administered to n subjects. The model for the effect 0.1 we Y=Bo+81X\i + €li, (1) while for the second drug it is Y2=Bo+B2X2; + €2i, (2) 1,...,n and X = X2 = 0. Assume that all observations are and in each case i independent and that for each i both E1 and e are normally distributed with mean 0 and variance a2 1. Obtain the...
Suppose we are given data on n observations (zi, Y4), i-1, . . . , n, and we have a linear model so that E(X)-β0+B1zi. Let A-SXY/SXX and A-Y-Aī be the least-square estimates given in lecture. (a) Show that E(Sxy)-ASxx and E(Y)-A +AF (b) Use (a) to show that E(BB and E(B)In other words, these are unbiased estimators (c) The fitted values Yi-A+Azi are used as estimates of %), and the residuals e,-x-Y; are used as surrogates for the unobservable...
2.3*) Graph the following observations of x and y on graph paper. X 12 3 4 5 6 la 10 8 55 23 bole (a) Using a ruler, draw a line that fits through the data. Measure the slope and intercept of the line you have drawn. (b) Use formulas (2.7) and (2.8) to compute, using only a hand calculator, the least squares estimates of the slope and the intercept. Plot this line on your graph. (c) Obtain the sample...