1 A STA4SA Assignment 1 Place your assignment solutions in the STA4SA pigeonhole in the boxes on the third level of PS2 Building before 5pm on Wednesday week 5. The first page of your solutions must carry (1) your name, (2) your student number. In submitting your work, you are consenting that it may be copied and transmitted by the University for detection of plagiarism. Please start with the following signed and dated statement of originality: \This is my own work. I have not copied any of it from anyone else." You have to include your GRASS and R commands, GRASS and R outputs, and plots into your submission (you can print them from GRASS and R). Name: Signature: Date: 1. Chose a GRASS command which was not considered in the lectures. Read GRASS help and search online to learn about this command. Write a short essay (3-4 pages, including pictures) about this command usage with an example of command’s application to some data or images. (5 marks) 2. Use the GRASS raster data elev state 500m and the vector data precip 30ynormals. (a) Plot the elevation map with stations’ locations on top in GRASS. (b) Read the data from GRASS into R. Plot May and November precipitations and annual precipitations in R. (c) Plot the locations of the meteorological stations in North Carolina using the elevation map as background in R. (d) Use the previous plots to suggest a spatial trend model. (e) Fit lm model for the November precipitation data using the longitude coordinate and the station elevation as explanatory variables. Plot maps with fitted values and residuals. (f) Fit lm model for the November precipitation data using first and second order polynomials of longitude and station elevation as explanatory variables. Plot maps with fitted values and residuals. (g) Compare the two models in (e) and (f) (use the mean square prediction error as a criterion). (5 marks)