Docsity
Log inSign up
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search Store documents

The best documents sold by students who completed their studies

Search through all study resources
Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

University Rankings

Discover the best universities in your country according to Docsity users

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

From our blog

Exams and Study
Go to the blog

Chapter Exercises - Problem Set 6 | ECON 160, Quizzes of Statistics

Clark UniversityStatistics
Prof. John C. Brown

Material Type: Quiz; Professor: Brown; Class: INTRO TO STATISTICAL ANALYSIS; Subject: Economics; University: Clark University; Term: Fall 2010;

Typology: Quizzes

2009/2010

Uploaded on 12/18/2010

djily02016
djily02016 🇺🇸

3

(1)

3 documents

1 / 2

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
Problem Set 6
Introduction to Statistics
Professor Tan
Due: Thursday, December 9 at 1:25 PM
Hand in at beginning of class or upload to Cicada
!
1.#Chapter#20,#Exercise#2#(Ch.#20;#Ex.2)#
Write!the!null!and!alternative!hypotheses!you!would!test!for!each!of!the!following:!
a.) In!the!1950s!only!about!40%!of!high!school!graduates!went!to!college.!Has!
that!percentage!changed?!
b.) 20%!of!cars!of!a!certain!model!have!needed!costly!transmission!work!ater!
being!driven!between!50,000!and!10,000!miles.!The!manufacturer!hopes!that!
the!redesign!of!a!transmission!component!has!solved!this!problem.!
c.) We!field‐test!a!new‐flavor!soft!drink,!planning!to!market!it!only!if!we!are!sure!
that!over!60%!of!the!people!like!flavor.!
!
2.#Ch.#20;#Ex.#22#
According!to!the!Association!of!American!Medical!Colleges,!only!46%!of!medical!
school!applicants!were!admitted!to!medical!school!in!the!fall!of!2006.!Upon!hearing!
this,!the!trustees!of!Striving!College!expressed!concern!that!only!77!of!the!180!
students!in!their!class!of!2006!who!applied!to!medical!school!were!admitted.!The!
college!president!assured!the!trustees!that!this!was!just!the!kind!of!year‐to‐year!
fluctuation!in!fortunes!that!is!to!be!expected!and!that,!in!fact,!the!school’s!success!
rate!was!consistent!with!the!national!average.!Who!is!right?!
a.) What!are!the!hypotheses?!
b.) Verify!that!the!conditions!are!satisfied!and!find!the!P‐Value!
c.) Are!the!trustees!right!to!be!concerned,!or!is!the!president!correct?!Explain.!
!
3.#Ch.#21;#Ex.#4#
Have!harsher!penalties!and!ad!campaigns!increased!seat‐belt!use!among!drivers!and!
passengers?!Observations!of!a!commuter!traffic!failed!to!find!evidence!of!a!
significant!change!compared!with!three!years!ago.!Explain!what!the!study’s!P‐Vaue!
of!0.17!means!in!this!context.!
!
4.#Ch.#21,#Ex.#18#
Testing!for!Alzheimer’s!disease!can!be!a!long!and!expensive!process,!consisting!of!
lengthy!tests!and!medical!diagnosis.!Recently,!a!group!of!researchers!(Solomon!et!
al.,!1998)!devised!a!7‐minute!test!to!serve!as!a!quick!screen!for!the!disease!for!use!in!
the!general!population!of!senior!citizens.!A!patient!who!is!testing!positive!would!
then!go!through!the!more!expensive!battery!of!tests!and!medical!diagnosis.!The!
authors!reported!a!false!positive!rate!of!4%!and!a!false!negative!rate!of!8%.!
a.) Put!this!in!the!context!of!a!hypothesis!test.!What!are!the!null!and!alternative!
hypotheses?!
b.) What!would!a!Type!I!Error!mean?!
c.) A!Type!II!Error?!
d.) Which!is!worse,!a!Type!I!or!Type!II!Error?!
e.) What!is!the!power!of!this!test?!
pf2

Partial preview of the text

Download Chapter Exercises - Problem Set 6 | ECON 160 and more Quizzes Statistics in PDF only on Docsity!

Problem Set 6 Introduction to Statistics Professor Tan Due: Thursday, December 9 at 1:25 PM Hand in at beginning of class or upload to Cicada

1. Chapter 20, Exercise 2 (Ch. 20; Ex.2) Write the null and alternative hypotheses you would test for each of the following: a.) In the 1950s only about 40% of high school graduates went to college. Has that percentage changed? b.) 20% of cars of a certain model have needed costly transmission work ater being driven between 50,000 and 10,000 miles. The manufacturer hopes that the redesign of a transmission component has solved this problem. c.) We field‐test a new‐flavor soft drink, planning to market it only if we are sure that over 60% of the people like flavor. 2. Ch. 20; Ex. 22 According to the Association of American Medical Colleges, only 46% of medical school applicants were admitted to medical school in the fall of 2006. Upon hearing this, the trustees of Striving College expressed concern that only 77 of the 180 students in their class of 2006 who applied to medical school were admitted. The college president assured the trustees that this was just the kind of year‐to‐year fluctuation in fortunes that is to be expected and that, in fact, the school’s success rate was consistent with the national average. Who is right? a.) What are the hypotheses? b.) Verify that the conditions are satisfied and find the P‐Value c.) Are the trustees right to be concerned, or is the president correct? Explain. 3. Ch. 21; Ex. 4 Have harsher penalties and ad campaigns increased seat‐belt use among drivers and passengers? Observations of a commuter traffic failed to find evidence of a significant change compared with three years ago. Explain what the study’s P‐Vaue of 0.17 means in this context. 4. Ch. 21, Ex. 18 Testing for Alzheimer’s disease can be a long and expensive process, consisting of lengthy tests and medical diagnosis. Recently, a group of researchers (Solomon et al., 1998) devised a 7‐minute test to serve as a quick screen for the disease for use in the general population of senior citizens. A patient who is testing positive would then go through the more expensive battery of tests and medical diagnosis. The authors reported a false positive rate of 4% and a false negative rate of 8%. a.) Put this in the context of a hypothesis test. What are the null and alternative hypotheses? b.) What would a Type I Error mean? c.) A Type II Error? d.) Which is worse, a Type I or Type II Error? e.) What is the power of this test?

**Problem Set 6 Introduction to Statistics Professor Tan Due: Thursday, December 9 at 1:25 PM Hand in at beginning of class or upload to Cicada

  1. Ch. 22, Ex. 36** In July of 2004, the Gallup Poll asked 1005 U.S. adults if they actively tried to avoid carbs in their diet. That number increased to 27% from 20% in a similar 2002 poll. Is this a significant increase? Explain. 6. Ch. 23, Ex. 3 Describe how the shape, center and spread of t‐models change as the number of degrees of freedom increases. 7. Ch. 23, Ex. 32 A company with a large fleet of cars hopes to keep gasoline costs down and sets a goal of attaining a fleet average of at least 26 miles per gallon. To see if the goal is being met, they check the gasoline usage for 50 company trips chosen at random, finding a mean of 25.02 mpg with a standard deviation of 4.83 mpg. Is this strong evidence that they have failed to attain their fuel goal? a.) – f.) Perform the 6‐Step Approach 8. Ch. 24, Ex. 32 Researchers randomly assigned participants to either a tall, thin “highball” glass or a short, thing “tumbler,” each of which held 355 ml. Participants were asked to pour a shot (1.5 oz.=44.3 ml) into their glass. Did the shape glass make a difference in how much liquid they poured? Here are the summaries: Highball Tumbler n 99 n 99 y‐bar 42.2 ml y‐bar 60.9 ml s 16.2 ml s 17.9 ml Test an appropriate hypothesis and state your conclusions. For assumptions and conditions that you cannot test, you may assume that they are sufficiently satisfied to proceed.