Introductory Statistics
Introductory Statistics
1st Edition
ISBN: 9781938168208
Author: Barbara Illowsky, Susan Dean
Publisher: OpenStax College
bartleby

Concept explainers

bartleby

Videos

Textbook Question
Book Icon
Chapter 8, Problem 97H

Suppose that an accounting firm does a study to determine the time needed to complete one person’s tax forms. It randomly surveys 100 people. The sample mean Is 23.6 hours. There Is a known standard deviation of 7.0 hours. The population distribution Is assumed to be normal.

a. i. x ¯ _____

ii. σ ______

iii. n=______

b. In words, define the random variables X and X ¯ .

c. Which distribution should you use for this problem? Explain your choice.

d. Construct a 90% confidence interval for the population mean time to complete the tax forms.

    i. State the confidence Interval.

ii. Sketch the graph.

iii. Calculate the error bound.

e. If the firm wished to increase Its level of confidence and keep the error bound the same by taking another survey what changes should It make?

f. If the firm did another survey, kept the error bound the same, and only surveyed 49 people, what would happen to the level of confidence? Why?

g. Suppose that the firm decided that it needed to be at least 96% confident of the population mean length of time to within one hour. How would the number of people the firm surveys change? Why?

Blurred answer
Students have asked these similar questions
30. An individual who has automobile insurance from a certain company is randomly selected. Let Y be the num- ber of moving violations for which the individual was cited during the last 3 years. The pmf of Y isy      | 1       2      4       8      16p(y) | .05   .10   .35   .40   .10 a.Compute E(Y).b. Suppose an individual with Y violations incurs a surcharge of $100Y^2. Calculate the expected amount of the surcharge.
24. An insurance company offers its policyholders a num- ber of different premium payment options. For a ran- domly selected policyholder, let X = the number of months between successive payments. The cdf of X is as follows: F(x)=0.00  :  x < 10.30  :  1≤x<30.40  :  3≤ x < 40.45  :  4≤ x <60.60  :  6≤ x < 121.00  :  12≤ x a. What is the pmf of X?b. Using just the cdf, compute P(3≤ X ≤6) and P(4≤ X).
59. At a certain gas station, 40% of the customers use regular gas (A1), 35% use plus gas (A2), and 25% use premium (A3). Of those customers using regular gas, only 30% fill their tanks (event B). Of those customers using plus, 60% fill their tanks, whereas of those using premium, 50% fill their tanks.a. What is the probability that the next customer will request plus gas and fill the tank (A2 B)?b. What is the probability that the next customer fills the tank?c. If the next customer fills the tank, what is the probability that regular gas is requested? Plus? Premium?

Chapter 8 Solutions

Introductory Statistics

Ch. 8 - A student polls his school to see If students In...Ch. 8 - Out of a random sample of 65 freshmen at State...Ch. 8 - The Berkman Center Study referenced in Example...Ch. 8 - Suppose an Internet marketing company wants to...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use (he following information to answer the next...Ch. 8 - Use (he following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer (he next...Ch. 8 - Use the following information o answer (he ne.t...Ch. 8 - Use the following information o answer (he ne.t...Ch. 8 - Use the following information o answer (he ne.t...Ch. 8 - Use the following information o answer the next...Ch. 8 - Use the following information answer the next six...Ch. 8 - Use the following information answer the next six...Ch. 8 - Use the following information answer the next six...Ch. 8 - Use the following information answer the next six...Ch. 8 - Use the following information answer the next six...Ch. 8 - Use the following information answer the next six...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use (he following information o answer the next...Ch. 8 - Use the following information o answer the next...Ch. 8 - Use the following information o answer the next...Ch. 8 - Use the following information o answer the next...Ch. 8 - Use the following information o answer the next...Ch. 8 - Use the following information o answer the next...Ch. 8 - Use the following information o answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Use the following information to answer the next...Ch. 8 - Among various ethnic groups, the standard...Ch. 8 - Announcements for 8.1 upcoming engineering...Ch. 8 - Suppose that an accounting firm does a study to...Ch. 8 - A sample of 16 small bags of the same brand of...Ch. 8 - A camp director is interested in the mean number...Ch. 8 - What Is meant by the tetm 90% confident when...Ch. 8 - The Federal Election Commission collects...Ch. 8 - The American Community Survey (ACS), part of the...Ch. 8 - The average height of young adult males has a...Ch. 8 - In six packages of The Flintstones Real Fruit...Ch. 8 - A random survey of enrollment at 35 community...Ch. 8 - Suppose that a committee is studying whether or...Ch. 8 - A pharmaceutical company makes tranquilizers. It...Ch. 8 - Suppose that 14 children, who were learning to...Ch. 8 - The Federal Election Commission (FEC) collects...Ch. 8 - Forbes magazine published data on the best small...Ch. 8 - Unoccupied seats on flights cause airlines to lose...Ch. 8 - In a recent sample of 84 used car sales costs, the...Ch. 8 - Six different national brands of chocolate chip...Ch. 8 - A survey of the mean number of cents off that...Ch. 8 - Use the following information o ansier the next...Ch. 8 - Use the following information o ansier the next...Ch. 8 - Insurance companies are interested In knowing the...Ch. 8 - Suppose that the insurance companies did do a...Ch. 8 - According to a recent survey of 1,200 people. 61%...Ch. 8 - An article regarding interracial dating and...Ch. 8 - Refer to the information In Exercise 8.120. a....Ch. 8 - Stanford University conducted a study of whether...Ch. 8 - A telephone poll of 1,000 adult Americans was...Ch. 8 - Refer to Exercise 8.123. Another question in the...Ch. 8 - Use the following informariton to answer the next...Ch. 8 - Use the following informariton to answer the next...Ch. 8 - Use the following informariton to answer the next...Ch. 8 - Use the following information to answer the next v...Ch. 8 - Use the following information to answer the next v...Ch. 8 - On May 23, 2013, Gallup reported that of the 1,005...Ch. 8 - A national survey of 1000 adults was conducted on...Ch. 8 - Public Policy Polling recently conducted a survey...Ch. 8 - You plan to conduct a survey on your college...Ch. 8 - In a recent Zogby International Poll, nine of .18...

Additional Math Textbook Solutions

Find more solutions based on key concepts
Knowledge Booster
Background pattern image
Statistics
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
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Glencoe Algebra 1, Student Edition, 9780079039897...
Algebra
ISBN:9780079039897
Author:Carter
Publisher:McGraw Hill
Statistics 4.1 Point Estimators; Author: Dr. Jack L. Jackson II;https://www.youtube.com/watch?v=2MrI0J8XCEE;License: Standard YouTube License, CC-BY
Statistics 101: Point Estimators; Author: Brandon Foltz;https://www.youtube.com/watch?v=4v41z3HwLaM;License: Standard YouTube License, CC-BY
Central limit theorem; Author: 365 Data Science;https://www.youtube.com/watch?v=b5xQmk9veZ4;License: Standard YouTube License, CC-BY
Point Estimate Definition & Example; Author: Prof. Essa;https://www.youtube.com/watch?v=OTVwtvQmSn0;License: Standard Youtube License
Point Estimation; Author: Vamsidhar Ambatipudi;https://www.youtube.com/watch?v=flqhlM2bZWc;License: Standard Youtube License