Intro Stats
4th Edition
ISBN: 9780321826275
Author: Richard D. De Veaux
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 22, Problem 45E
Grades, again In some situations where the expected cell counts are too small, as in the case of the grades given by Professors Alpha and Beta in Exercise 43, we can complete an analysis anyway. We can often proceed after combining cells in some way that makes sense and also produces a table in which the conditions are satisfied. Here, we create a new table displaying the same data, but calling D’s and F’s “Below C”:
| Prof. Alpha | Prof. Beta | |
| A | 3 | 9 |
| B | 11 | 12 |
| C | 14 | 8 |
| Below C | 12 | 3 |
- a) Find the expected counts for each cell in this new table, and explain why a chi-square procedure is now appropriate.
- b) With this change in the table, what has happened to the number of degrees of freedom?
- c) Test your hypothesis about the two professors, and state an appropriate conclusion.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
#28). Both pictures are the same equation.
You are interested in exploring gender differences in sentence length for convicted sex offenders. You take a sample of 18 male sex offenders and a
sample of 13 female sex offenders and compute the average sentence length for each group in years. Based on the information below, is there a
significant difference between males and females in the average sentence length for convicted sex offenders? Use alpha = .10.
%3D
Males:
Females:
n = 18
n = 13
M= 26.3
SS = 880
M = 21.7
SS = 610
Step 1:
2a. Identify the null hypothesis. Type a - f here
a. Ho: Hm = Hf
%3D
b. Ho: Hm # Hf
c. Ho: Hm 2 Hf
d. Ho: Hm SHf
e. Ho: m > Hf
f. Ho: Hm Hf
f. Hj: Hm < Hr
Step 2:
2c. Type in your df here:
A
B
The managers of a brokerage firm are interested in finding out if the number of new clients a
broker brings into the firm affects the sales generated by the broker. They sample 12 brokers and
determine the number of new clients they have enrolled in the last year and their sales amounts in
thousands of dollars. These data are partially presented in the table with the following results:
SST=1564.2, SSR=1227, E(X₁-X)² = 979.7 and Ŷ = 17.7+ 1.12X.
D
Broker Clients (X) Sales (Y)
1
2
:
12
27
11
:
22
The 95% confidence interval estimate for the slope is
0.471 to 1.932
0.856 to 1.636
0.532 to 1.708
:
0.707 to 1.533
52
37
38
......
to.....
Chapter 22 Solutions
Intro Stats
Ch. 22.3 - Why do we need the control group?Ch. 22.3 - Prob. 2JCCh. 22.3 - Prob. 3JCCh. 22.3 - Prob. 4JCCh. 22.3 - Prob. 5JCCh. 22.3 - Prob. 6JCCh. 22.4 - Prob. 7JCCh. 22.4 - Prob. 8JCCh. 22.4 - Prob. 9JCCh. 22 - Human births If there is no seasonal effect on...
Ch. 22 - Bank cards At a major credit card bank, the...Ch. 22 - Prob. 3ECh. 22 - Prob. 4ECh. 22 - Customer ages An analyst at a local bank wonders...Ch. 22 - Bank cards, once more A market researcher working...Ch. 22 - Human births, last time For the data in Exercise...Ch. 22 - Prob. 8ECh. 22 - Prob. 9ECh. 22 - Prob. 10ECh. 22 - Prob. 11ECh. 22 - Prob. 12ECh. 22 - Dice After getting trounced by your little brother...Ch. 22 - MMs As noted in an earlier chapter, Mars Inc. says...Ch. 22 - Nuts A company says its premium mixture of nuts...Ch. 22 - Prob. 16ECh. 22 - NYPD and race Census data for New York City...Ch. 22 - Violence against women In its study When Men...Ch. 22 - Fruit flies Offspring of certain fruit flies may...Ch. 22 - Prob. 20ECh. 22 - Prob. 21ECh. 22 - Lottery numbers The fairness of the South African...Ch. 22 - Prob. 23ECh. 22 - Prob. 24ECh. 22 - Childbirth, part 2 In Exercise 23, the table shows...Ch. 22 - Prob. 26ECh. 22 - Prob. 27ECh. 22 - Prob. 28ECh. 22 - Prob. 29ECh. 22 - Does your doctor know? (part 4) In Exercises 24,...Ch. 22 - Prob. 31ECh. 22 - Prob. 32ECh. 22 - 33. Titanic Here is a table we first saw in...Ch. 22 - NYPD The table below shows the rank attained by...Ch. 22 - Prob. 35ECh. 22 - NYPD again Examine and comment on this table of...Ch. 22 - Cranberry juice Its common folk wisdom that...Ch. 22 - Prob. 38ECh. 22 - Montana A poll conducted by the University of...Ch. 22 - 40. Fish diet Medical researchers followed 6272...Ch. 22 - Prob. 41ECh. 22 - Working parents In April 2009, Gallup published...Ch. 22 - Grades Two different professors teach an...Ch. 22 - Full moon Some people believe that a full moon...Ch. 22 - Grades, again In some situations where the...Ch. 22 - Full moon, next phase In Exercise 44, you found...Ch. 22 - Racial steering A subtle form of racial...Ch. 22 - 48. Titanic, redux Newspaper headlines at the...Ch. 22 - Prob. 49ECh. 22 - Prob. 50ECh. 22 - Prob. 51ECh. 22 - Education by age Use the survey results in the...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.Similar questions
- Find the equation of the regression line for the following data set. x 1 2 3 y 0 3 4arrow_forwardUrban Travel Times Population of cities and driving times are related, as shown in the accompanying table, which shows the 1960 population N, in thousands, for several cities, together with the average time T, in minutes, sent by residents driving to work. City Population N Driving time T Los Angeles 6489 16.8 Pittsburgh 1804 12.6 Washington 1808 14.3 Hutchinson 38 6.1 Nashville 347 10.8 Tallahassee 48 7.3 An analysis of these data, along with data from 17 other cities in the United States and Canada, led to a power model of average driving time as a function of population. a Construct a power model of driving time in minutes as a function of population measured in thousands b Is average driving time in Pittsburgh more or less than would be expected from its population? c If you wish to move to a smaller city to reduce your average driving time to work by 25, how much smaller should the city be?arrow_forwardOlympic Pole Vault The graph in Figure 7 indicates that in recent years the winning Olympic men’s pole vault height has fallen below the value predicted by the regression line in Example 2. This might have occurred because when the pole vault was a new event there was much room for improvement in vaulters’ performances, whereas now even the best training can produce only incremental advances. Let’s see whether concentrating on more recent results gives a better predictor of future records. (a) Use the data in Table 2 (page 176) to complete the table of winning pole vault heights shown in the margin. (Note that we are using x=0 to correspond to the year 1972, where this restricted data set begins.) (b) Find the regression line for the data in part ‚(a). (c) Plot the data and the regression line on the same axes. Does the regression line seem to provide a good model for the data? (d) What does the regression line predict as the winning pole vault height for the 2012 Olympics? Compare this predicted value to the actual 2012 winning height of 5.97 m, as described on page 177. Has this new regression line provided a better prediction than the line in Example 2?arrow_forward
- What does the y -intercept on the graph of a logistic equation correspond to for a population modeled by that equation?arrow_forwardA special education teacher did research on whether or not there is a relationship between the number of students in his class and the number incidents of “acting out” behaviors exhibited by the autistic students in the classroom. He collects data for a year and aggregates them by month. He obtained the statistics below, r= -.863 R2=.74 b= -1.212294 a= 131.176598 10.) How does the presence of more students affect the incidents in the class? a) as students are added the incidences increase b) as students are added the incidences decrease c) the number of students does not affect acting out d) the number of students caused more incidents How much of the variability of acting out is explained by the number of students in the class?___________arrow_forwardHow profitable are different sectors of the stock market? One way to answer such a question is to examine profit as a percentage of stockholder equity. A random sample of 32 retail stocks was studied for x1, profit as a percentage of stockholder equity. The result was x1 = 13.2. A random sample of 33 utility (gas and electric) stocks was studied for x2, profit as a percentage of stockholder equity. The result was x2 = 10.0. Assume ?1 = 4.2 and ?2 = 2.6. Note: For degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some cases, this choice will increase the P-value by a small amount or increase the length of the confidence interval, thereby making the answer slightly more "conservative." (a) Let ?1 represent the population mean profit as a percentage of stockholder equity for retail stocks, and let ?2 represent the population mean profit as a percentage of stockholder equity for utility stocks. Find a 95% confidence interval for ?1 − ?2.…arrow_forward
arrow_back_ios
arrow_forward_ios
Recommended textbooks for you
Linear Algebra: A Modern IntroductionAlgebraISBN:9781285463247Author:David PoolePublisher:Cengage Learning
Functions and Change: A Modeling Approach to Coll...AlgebraISBN:9781337111348Author:Bruce Crauder, Benny Evans, Alan NoellPublisher:Cengage Learning
College AlgebraAlgebraISBN:9781305115545Author:James Stewart, Lothar Redlin, Saleem WatsonPublisher:Cengage Learning
Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill
Big Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt
Algebra and Trigonometry (MindTap Course List)AlgebraISBN:9781305071742Author:James Stewart, Lothar Redlin, Saleem WatsonPublisher:Cengage Learning
Linear Algebra: A Modern Introduction
Algebra
ISBN:9781285463247
Author:David Poole
Publisher:Cengage Learning
Functions and Change: A Modeling Approach to Coll...
Algebra
ISBN:9781337111348
Author:Bruce Crauder, Benny Evans, Alan Noell
Publisher:Cengage Learning
College Algebra
Algebra
ISBN:9781305115545
Author:James Stewart, Lothar Redlin, Saleem Watson
Publisher:Cengage Learning
Glencoe Algebra 1, Student Edition, 9780079039897...
Algebra
ISBN:9780079039897
Author:Carter
Publisher:McGraw Hill
Big Ideas Math A Bridge To Success Algebra 1: Stu...
Algebra
ISBN:9781680331141
Author:HOUGHTON MIFFLIN HARCOURT
Publisher:Houghton Mifflin Harcourt
Algebra and Trigonometry (MindTap Course List)
Algebra
ISBN:9781305071742
Author:James Stewart, Lothar Redlin, Saleem Watson
Publisher:Cengage Learning
Continuous Probability Distributions - Basic Introduction; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=QxqxdQ_g2uw;License: Standard YouTube License, CC-BY
Probability Density Function (p.d.f.) Finding k (Part 1) | ExamSolutions; Author: ExamSolutions;https://www.youtube.com/watch?v=RsuS2ehsTDM;License: Standard YouTube License, CC-BY
Find the value of k so that the Function is a Probability Density Function; Author: The Math Sorcerer;https://www.youtube.com/watch?v=QqoCZWrVnbA;License: Standard Youtube License