II. Problem - Use SAS for your computations. You have to show your work. No credit without an explanation (8 marks each). 1. We are interested in the factors explaining whether consumers make online purchases or not. A questionnaire was administered with a sample of 435 people. The data are in the file psl.sas7bdat the 324_data folder. Here is the variables description: . Sex: 0=male, 1=female; . Age - in years; . Purchase: 1=online purchase made last year, 0=no online purchase made last year; Variables X1 to X34 are measured on a scale 1 to 7 where 1=strongly disagree and 7-strongly agree and are the answers to the question: "Indicate to what extent you agree with the following statements": 1 Talways purchase the types of products I want from the Internet 2 There is a high risk for purchasing online 3 Internet retailers encourage me to make suggestions 4 The Internet retailers' websites provide in-depth information to answer my questions S I can buy the products that are not available in retail shops through the Internet 6 The website designs of the Internet retailers are aesthetically attractive 7 Online shopping is not as secure as traditional retail shopping I do not feel secure about providing my bank card details to a payment platform 9 I have regular access to a computer 10 | Internet shopping offers a wide variety of products 1 1 Online shopping offers better value for my money compared to traditional retail shoppi 12 |Family/friends encourage me to make purchases through the Internet 13 Online shopping allows me to bay the same, or similar products, at cheaper prices than traditional retailing stores 14 It is casy to receive a personalized customer service from an Internet retailer 15 Online shopping allows me to save money as I do not need to pay transportation costs 16 It is quick and easy for me to complete a transaction through the website 17 It takes only a little time and effort to make a purchase through the Internet 18 I have knowledge about how to make pur es through the Internet 19 I have regular access to the Internet 20 Internet retailers offer good after sales service 21 Internet retailers understand my needs 22 I am very skilled at using the Internet 23 I am not confident that the information I provide to an Internet retailer is not used for other purposes 24 Internet retailers honour their product guarantees 25 I am not confident that my personal information is protected by an Internet retailer 26 The products I ordered are delivered to me within the time promised by the Intemet retailers The quantity and quality of the products I receive from Internet retailers are exactly the same as 1 order Internet shopping saves me time. so I can do other activities 9 The links within the website allow me to move back and forth casily between pages of the website 30 It is more convenient to shop through the Internet when compared to traditional retail shopping 31 Internet retailers' websites are easy to navigate 32 I think the Internet offers lower prices compared to retail stores 33 Marketing communication influenced my decision to make purchases through the Internet 34 The media influenced my decision (a) Provide descriptive statistics for the variables "Sex", "Age" and "Purchase". (b) Present in a table the mean and standard deviation of each of the 34 variables X1-X34 ordered from the highest to the lowest value of the mean. Which of them seem the most important? (c) Present the means of the 34 Xs for women and men separately. Are there any differences? (d) Do a Linear Probability Model (LPM) with the variable "Purchase" as a dependent variable and 36 independent variables - 34 Xs, "Sex" and "Age". Test them for statistical significance at 1% and interpret the ones that are. (e) Do a Logistic regression model (Logit) with the same variables as in (d). Test for statistical significance at 1% and interpret the coefficients that are. Are they different that the ones with the LPM? A (f) Now do a Logit with only X1-X17 in addition to "Age" and "Sex". Which of the two models is preferable - logit with all or with half the Xs in addition to "Age" and "Sex"? (g) The data file psi-g.xisx contains one line - the profile of a potential respondent. Using the unrestricted Logit model (with all 36 explanatory variables) estimate the probability and the 95% confidence interval that that person made a purchase last year. (h) Do the same with the restricted Logit model (with "Age", "Sex" and X1-X17) - which of the two predictions is more precise and why? A P.ps 1.sas/bdat x : Program 1 x View: Column names Filter: (none) Columns Total rows: 435 Total columns: 37 Select all X1 X2 123 X1 13 X2 NO W 123 x 3 w a W W N 123 x4 123 x 5 W N 123 X6 123 X7 123 X8 123 x10 123 x 11 in U W W a D D W 123 x 12 123 x13 14 123 x 14 (@a v 15 16 Property Value 17 Label *31 18 W Name x31 19 Length 8 20 Type Numeric 21 Format 22 Informat 23 24 V w W UT D 25 26ps 1.sas7bdat x 1 Program 1 x CODE LOG RESULTS Line # PROC SQL; 2 CREATE TABLE WORK . query AS W SELECT x1 , x2 , x3 , x4 , x5 , x6 , x7 , x8 , x9 , x10 , x11 , x 4 RUN; 5 QUIT ; PROC DATASETS NOLIST NODETAILS; 8 CONTENTS DATA=WORK. query OUT=WORK. details; 9 RUN; 10 PROC PRINT DATA=WORK . details; 12 RUN;14 selection2_all_subset.sas 21 selection3_cv.sas Li selection4_interaction.sas 324_data #: aapl.sas7bdat [x aapl.xls accident.sas7bdat cluster1.sas7bdat BEcluster1a.sas7bdat dom.sas7bdat dommissing.sas7bdat ama elnino.sas7bdat 030 intention.sas7bdat intro_ex 1.sas7bdat logit1.sas7bdat logit6.sas7 bdat 88: missing 1.sas/ bdat ps 1.sas/ bdat x ps1_g.xisx ps2.sas7bdat 18: ps2q2.sas/ bdat ps2q2d.sas7bdat ps2_score.sas/bdat 15 selection 1_test.sas/bdat selection 1_train.sas7bdat Sasuser.v94