hyptestreview_sol

# Hyptestreview_sol - Hypothesis Testing Review Exercises Solutions 1 Business Week/Harris poll Variables whether or not a respondent thinks the U.S

This preview shows pages 1–4. Sign up to view the full content.

Hypothesis Testing Review Exercises Solutions 1. Business Week/Harris poll Variables: whether or not a respondent thinks the U.S. is competing well (good/excellent) in the global economy and time (1996 or 2000) Parameters: p 1996 = proportion of all U.S. adults who thought the U.S. was competing well in 1996 p 2000 = proportion of all U.S. adults who thought the U.S. was competing well in 2000 Ho: p 1996 = p 2000 Ha: p 1996 < p 2000 Sample size check: 15 331 ) ˆ 1 ( 15 704 ˆ 15 422 ) ˆ 1 ( 15 582 ˆ 2000 2000 2000 2000 1996 1996 1996 1996 = - = = - = p n p n p n p n Sample size check holds, so use the z-test for two proportions. 6307 . 2039 1286 1035 1004 704 582 ˆ = = + + = p 70 . 4 1035 1 1004 1 ) 2039 / 1286 1 ( 2039 / 1286 0 ) 1035 / 704 1004 / 582 ( 1 1 ) ˆ 1 ( ˆ ) ˆ ˆ ( 2000 1996 0 2000 1996 - = + - - - = + - - - = n n p p D p p z Test and CI for Two Proportions Sample X N Sample p 1 582 1004 0.579681 2 704 1035 0.680193 Difference = p (1) - p (2) Estimate for difference: -0.100512 95% upper bound for difference: -0.0655089 Test for difference = 0 (vs < 0): Z = -4.70 P-Value = 0.000 p-value < .00003 rejection region : z < –1.645 (using α = .05) reject Ho. We have strong evidence that the proportion of all adults responding good/excellent has increased over the 4 years from 1996 to 2000.

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

View Full Document
2. National TV telethon Variables: donation amount and gender Parameters: σ m 2 = variance of donation amounts for all males σ f 2 = variance of donation amounts for all females Ho: σ m 2 = σ f 2 Ha: σ m 2 σ f 2 F-test for two variances 48 . 3 34 . 1 50 . 2 2 2 2 2 arg = = = smaller er l s s F df num = 25 – 1 = 24 df den = 25 – 1 = 24 p-value < .01 (Minitab: .003) rejection region: F > 2.27 reject Ho. We have enough evidence that donations from males and females differ in variability of amounts. 95%  Bonferroni Confidence Intervals for StDevs 2 1 4.0 3.5 3.0 2.5 2.0 1.5 1.0 F-Test Test Statistic 3.48 P-Value 0.003 Test for Equal Variances
3. Fit and Trim Variable: weight loss Parameter: μ = mean weight loss for all clients of Fit and Trim Ho: μ 10 Ha: μ > 10 n = 20 < 30, assume weight losses are normally distributed, σ unknown use t-test 118 . 1

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 12/07/2011 for the course MATH 201 taught by Professor Crissinger during the Fall '08 term at University of Delaware.

### Page1 / 10

Hyptestreview_sol - Hypothesis Testing Review Exercises Solutions 1 Business Week/Harris poll Variables whether or not a respondent thinks the U.S

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online