# 420Hw07 - STAT 420(10 points(due Friday March 14 by 4:00...

This preview shows pages 1–2. Sign up to view the full content.

STAT 420 Spring 2008 Homework #7 (10 points) (due Friday, March 14, by 4:00 p.m.) 1. A forester seeking information on basic tree dimensions obtains the following measurements of the diameters 4.5 feet above the ground and the heights of 12 sugar maple trees. The forester wishes to determine if the diameter measurements can be used to predict the tree height. Diameter x (inches) 0.9 1.2 2.9 3.1 3.3 3.9 4.3 6.2 9.6 12.6 16.1 25.8 Height y (feet) 18 26 32 36 44.5 35.6 40.5 57.5 67.3 84 67 87.5 a) Make a scatterplot of x vs. y . Does a straight-line relationship seem appropriate? b) Make a scatterplot of x ' = ln x vs. y ' = ln y . Does a straight-line relationship seem appropriate? c) Fit a straight-line regression to the transformed data. Add the least-squares regression line to the scatterplot from part(b). Comment on the adequacy of the fit. d) Construct a 95% prediction interval for the height of the tree y with the diameter x = 10 inches. Hint: Construct a 95% prediction interval for

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 02/10/2009 for the course STAT 420 taught by Professor Stepanov during the Spring '08 term at University of Illinois at Urbana–Champaign.

### Page1 / 2

420Hw07 - STAT 420(10 points(due Friday March 14 by 4:00...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online