hw2solution - STAT 226 Problem 1. (a) Homework 2 Solution...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
STAT 226 Homework 2 Solution Total points: 120 Problem 1. (a) FALSE (Error--Any curve)—Correct Æ Any curve that approximates a histogram and has an area of one under it is a density curve. [Note: We can adjust the scale(s) of the histogram so that an approximate curve can become a density curve. See text example 1.15 (with figures) of page 52-53. JMP automatically gives a density curve under fit distribution Æ smooth curve .] (b) FALSE (Error--any)—Correct Æ Mean and median of symmetric distributions are always equal. (c) FALSE (Error--any distribution)—Correct Æ The 68–95–99.7 Rule applies to normal distributions only. (d) FALSE Correct Æ The standard deviation of a set of observations is only equal to zero, when all observations are of the same value. (e) TRUE (f) TRUE (g) FALSE (Error --larger the z-score)—Correct Æ The smaller the absolute value of the z-score of an observation the closer this observation is to the mean of the distribution. ( Note: there are other ways to correct/write this) (h) FALSE (Error—mean)—correct Æ According to the 68–95–99.7 Rule, the range of a data set coming from a Normal distribution is approximately equal to six times the standard deviation . F Problem 2. a) 0.0495 b) 0.0793
Background image of page 1

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

View Full DocumentRight Arrow Icon
Using Table A, Area above 1.41=1- area under 1.41=1-0.9207 = 0.0793 c) 0.8712 Using Table A, area between -1.65 and 1.41 = Area under1.41 – Area under (-1.65) = 0.9207 – 0.0495 = 0.8712 d) Yes. We know that the total area under a density curve is equal to 1. From the shaded
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/05/2010 for the course STAT 226 taught by Professor Abbey during the Fall '08 term at Iowa State.

Page1 / 6

hw2solution - STAT 226 Problem 1. (a) Homework 2 Solution...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online