HW2sol

# HW2sol - 1. An investigative study collected 50...

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1. An investigative study collected 50 observations from the Wabash river at random locations near Lafayette. Each observation consisted of a measure of water pH (X) and fish count (Y). The researchers are interested in how the acidity of the water affects the number of fish. Complete the following ANOVA table for the regression analysis (the P-value need not be exact). State the null and alternative hypotheses for the F-test as well as your conclusion in sentence form. Sum of Mean Source DF Squares Square F Value Pr > F Model __1_ 45.20 45.2 _452 <.0001 Error _48_ 4.8_ _0.1 Corrected Total _49_ 50.00 H 0 : 1 = 0; H A : 1 0. We reject H 0 and conclude that there is a significant linear relationship between water pH and fish count. 2. For this problem use the “grade point average” data described in KNNL Problem #1.19. The data are on the disk that accompanies the text and can also be found on the class web site (CH01PR19.DAT) . Make sure you understand which column is X and which is Y and read in the data accordingly. See Topic 1, p. 16 or nknw060.sas for an example of how to read in a data file. (a) Plot the data using PROC GPLOT . Include a smoothed function on the plot by preceding the plot statement with “ SYMBOL1 i=smNN where NN is a number between 1 and 99. Note that larger numbers cause greater smoothing. Make sure to indicate the smoothing number in the title of the plot. Is the relationship approximately linear?

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The relationship looks approximately linear. (b) Run a linear regression to predict GPA based on the entrance exam. Give the complete ANOVA table for this regression.
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## This note was uploaded on 02/05/2011 for the course STAT 512 taught by Professor Staff during the Spring '08 term at Purdue.

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HW2sol - 1. An investigative study collected 50...

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