Introduction to Statistics and Data Analysis

5th Edition

ISBN: 9781305115347

Author: Roxy Peck; Chris Olsen; Jay L. Devore

Publisher: Brooks Cole

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Estimation

A new framework of data analysis where the new statistical methods are used for interpreting the results and analyzing the data is known as estimation in statistics.

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Textbook Question

Chapter 7, Problem 19CRE

Consider the variable

x = time required for a college student to complete a standardized exam

Suppose that for the population of students at a particular university, the distribution of x is well approximated by a normal distribution with mean 45 minutes and standard deviation 5 minutes.

a. If 50 minutes is allowed for the exam, what proportion of students at this university would be unable to finish in the allotted time?
b. How much time should be allowed for the exam if we wanted 90% of the students taking the test to be able to finish in the allotted time?
c. How much time is required for the fastest 25% of all students to complete the exam?

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

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Chapter 7 Solutions

Introduction to Statistics and Data Analysis

Ch. 7.1 - State whether each of the following random...Ch. 7.1 - Classify each of the following random variables as...Ch. 7.1 - Starting at a particular time, each car entering...Ch. 7.1 - A point is randomly selected from the interior of...Ch. 7.1 - A point is randomly selected on the surface of a...Ch. 7.1 - Prob. 6E Ch. 7.1 - A box contains four slips of paper marked 1, 2, 3,...Ch. 7.2 - Let x be the number of courses for which a...Ch. 7.2 - Let y denote the number of broken eggs in a...Ch. 7.2 - Suppose that fund-raisers at a university call...

Ch. 7.2 - Airlines sometimes overbook flights. Suppose that...Ch. 7.2 - Suppose that a computer manufacturer receives...Ch. 7.2 - Simulate the chance experiment described in the...Ch. 7.2 - Of all airline flight requests received by a...Ch. 7.2 - Suppose that 20% of all homeowners in an...Ch. 7.2 - A box contains five slips of paper, marked 1, 1,...Ch. 7.2 - Components coming off an assembly line are either...Ch. 7.2 - A contractor is required by a county planning...Ch. 7.2 - A library subscribes to two different weekly news...Ch. 7.3 - Let x denote the lifetime (in thousands of hours)...Ch. 7.3 - A particular professor never dismisses class...Ch. 7.3 - Refer to the probability distribution given in the...Ch. 7.3 - The article “Modeling Sediment and Water Column...Ch. 7.3 - Let x denote the amount of gravel sold (in tons)...Ch. 7.3 - Let x be the amount of time (in minutes) that a...Ch. 7.3 - Prob. 26E Ch. 7.4 - Consider selecting a household in rural Thailand...Ch. 7.4 - Suppose the probability distribution of x, the...Ch. 7.4 - Consider the following probability distribution...Ch. 7.4 - Referring to the previous exercise, use the result...Ch. 7.4 - Exercise 7.8 gave the following probability...Ch. 7.4 - Prob. 32E Ch. 7.4 - Prob. 33E Ch. 7.4 - Suppose that for a particular computer...Ch. 7.4 - A local television station sells 15-second,...Ch. 7.4 - An author has written a book and submitted it to a...Ch. 7.4 - A grocery store has an express line for customers...Ch. 7.4 - Prob. 38E Ch. 7.4 - To assemble a piece of furniture, a wood peg must...Ch. 7.4 - A multiple-choice exam consists of 50 questions....Ch. 7.4 - Prob. 41E Ch. 7.4 - Prob. 42E Ch. 7.5 - Prob. 43E Ch. 7.5 - The Los Angeles Times (December 13, 1992) reported...Ch. 7.5 - Refer to the previous exercise, and suppose that...Ch. 7.5 - Twenty-five percent of the customers of a grocery...Ch. 7.5 - Example 7.18 described a study in which a person...Ch. 7.5 - Prob. 49E Ch. 7.5 - A breeder of show dogs is interested in the number...Ch. 7.5 - Prob. 51E Ch. 7.5 - Prob. 52E Ch. 7.5 - Suppose that the probability is 0.1 that any given...Ch. 7.5 - Suppose that 30% of all automobiles undergoing an...Ch. 7.5 - Suppose that you will take a multiple-choice exam...Ch. 7.5 - Suppose that 20% of the 10,000 signatures on a...Ch. 7.5 - Prob. 57E Ch. 7.5 - Prob. 58E Ch. 7.5 - Suppose a playlist on an MP3 music player consists...Ch. 7.5 - Sophie is a dog that loves to play catch....Ch. 7.5 - Suppose that 5% of cereal boxes contain a prize...Ch. 7.5 - Prob. 62E Ch. 7.6 - Prob. 63E Ch. 7.6 - Prob. 64E Ch. 7.6 - Prob. 65E Ch. 7.6 - Prob. 66E Ch. 7.6 - Let z denote a variable that has a standard normal...Ch. 7.6 - Determine the value z that a. Separates the...Ch. 7.6 - Determine the value of z such that a. z and z...Ch. 7.6 - Because P(z 0.44) = 0.67, 67% of all z values are...Ch. 7.6 - Consider the population of all 1-gallon cans of...Ch. 7.6 - Consider babies born in the “normal” range of...Ch. 7.6 - Prob. 73E Ch. 7.6 - The paper referenced in Example 7.30 (Estimating...Ch. 7.6 - The size of the left upper chamber of the heart is...Ch. 7.6 - The paper referenced in the previous exercise also...Ch. 7.6 - According to the paper "Commuters' Exposure to...Ch. 7.6 - A machine that cuts corks for wine bottles...Ch. 7.6 - Refer to the previous exercise. Suppose that there...Ch. 7.6 - A gasoline tank for a certain car is designed to...Ch. 7.6 - The time that it takes a randomly selected job...Ch. 7.6 - Suppose that the distribution of typing speed in...Ch. 7.7 - The authors of the paper Development of...Ch. 7.7 - The paper Risk Behavior, Decision Making, and...Ch. 7.7 - Prob. 85E Ch. 7.7 - Macular degeneration is the most common cause of...Ch. 7.7 - Prob. 87E Ch. 7.7 - Consider the following 10 observations on the...Ch. 7.7 - Prob. 89E Ch. 7.7 - Prob. 90E Ch. 7.7 - Prob. 91E Ch. 7.7 - Prob. 92E Ch. 7.7 - The figure on the next page appeared in the paper...Ch. 7.8 - Let x denote the IQ of an individual selected at...Ch. 7.8 - Suppose that the distribution of x = the number of...Ch. 7.8 - The number of vehicles leaving a turnpike at a...Ch. 7.8 - Prob. 97E Ch. 7.8 - Prob. 98E Ch. 7.8 - Prob. 99E Ch. 7.8 - Suppose that 70% of the bicycles sold by a certain...Ch. 7.8 - Suppose that 25% of the fire alarms in a large...Ch. 7.8 - Suppose that 65% of all registered voters in a...Ch. 7.8 - Flashlight bulbs manufactured by a certain company...Ch. 7.8 - A company that manufactures mufflers for cars...Ch. 7 - Let x denote the duration of a randomly selected...Ch. 7 - A soft-drink machine dispenses only regular Coke...Ch. 7 - Prob. 107CR Ch. 7 - Refer 10 the probability distribution given in...Ch. 7 - A new batterys voltage may be acceptable (A) or...Ch. 7 - A pizza company advertises that it puts 0.5 pounds...Ch. 7 - Suppose that fuel efficiency for a particular...Ch. 7 - A coin is flipped 25 times. Let x be the number of...Ch. 7 - The probability distribution of x, the number of...Ch. 7 - The amount of time spent by a statistical...Ch. 7 - The lifetime of a certain brand of battery is...Ch. 7 - A machine producing vitamin E capsules operates so...Ch. 7 - The Wall Street Journal (February 15, 1972)...Ch. 7 - The longest run of Ss in the sequence SSFSSSSFFS...Ch. 7 - Prob. 119CR Ch. 7 - Four peoplea, b, c, and dare waiting to give...Ch. 7 - Kyle and Lygia are going to play a series of...Ch. 7 - Prob. 122CR Ch. 7 - Suppose that your statistics professor tells you...Ch. 7 - Suppose that the pH of soil samples taken from a...Ch. 7 - The lightbulbs used to provide exterior lighting...Ch. 7 - Suppose there are approximately 40,000 travel...Ch. 7 - Prob. 1CRE Ch. 7 - Prob. 2CRE Ch. 7 - Prob. 3CRE Ch. 7 - Prob. 4CRE Ch. 7 - Prob. 5CRE Ch. 7 - Prob. 6CRE Ch. 7 - Two shipping services offer overnight delivery of...Ch. 7 - Prob. 8CRE Ch. 7 - Prob. 9CRE Ch. 7 - The Cedar Rapids Gazette (November 20, 1999)...Ch. 7 - Prob. 11CRE Ch. 7 - The article Men, Women at Odds on Gun Control...Ch. 7 - Suppose that a new Internet company Mumble.com...Ch. 7 - Refer to the previous exercise. Suppose that...Ch. 7 - A chemical supply company currently has in stock...Ch. 7 - Prob. 16CRE Ch. 7 - An experiment was conducted to investigate whether...Ch. 7 - A machine that produces ball bearings has...Ch. 7 - Consider the variable x = time required for a...Ch. 7 - Prob. 20CRE Ch. 7 - Prob. 21CRE

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Solution Summary: The author explains how the proportion of students at this university would be unable to finish a standardized exam in the allotted time is 0.1587.

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Chapter 7 Solutions