Introductory Statistics
1st Edition
ISBN: 9781938168208
Author: Barbara Illowsky, Susan Dean
Publisher: OpenStax College
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Textbook Question
Chapter 7, Problem 76H
The attention span of a two-year-old is exponentially distributed with a
a. InwordsX ______
b.X” ( )
c. In words. X _____________
d. X ___(______
e. Befoic doing any calculations, which do you think will be higher? Explain why.
I. The
U. The probability that the average attention span for the 60 chIldren Is less than ten minutes?
f. Calculate the probabilities in pan e.
g. Explain why the distribution for X is not exponential.
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3. Bayesian Inference – Updating Beliefs
A medical test for a rare disease has the following characteristics:
Sensitivity (true positive rate): 99%
Specificity (true negative rate): 98%
The disease occurs in 0.5% of the population.
A patient receives a positive test result.
Questions:
a) Define the relevant events and use Bayes’ Theorem to compute the probability that the patient actually has the disease.b) Explain why the result might seem counterintuitive, despite the high sensitivity and specificity.c) Discuss how prior probabilities influence posterior beliefs in Bayesian inference.d) Suppose a second, independent test with the same accuracy is conducted and is also positive. Update the probability that the patient has the disease.
4. Linear Regression - Model Assumptions and Interpretation
A real estate analyst is studying how house prices (Y) are related to house size in square feet (X). A simple
linear regression model is proposed:
The analyst fits the model and obtains:
•
Ŷ50,000+150X
YBoB₁X + €
•
R² = 0.76
• Residuals show a fan-shaped pattern when plotted against fitted values.
Questions:
a) Interpret the slope coefficient in context.
b) Explain what the R² value tells us about the model's performance.
c) Based on the residual pattern, what regression assumption is likely violated? What might be the
consequence?
d) Suggest at least two remedies to improve the model, based on the residual analysis.
Chapter 7 Solutions
Introductory Statistics
Ch. 7 - An unknown distribution has a mean of 45 and a...Ch. 7 - The length of time taken on the SAT for a group of...Ch. 7 - In an article on Flurry Blog. a gaming marketing...Ch. 7 - Cans of a cola beverage claim to contain 16...Ch. 7 - An unknown distribution has a mean of 45 and a...Ch. 7 - In a recent study reported Oct.29, 2012 on the...Ch. 7 - The mean number of minutes for app engagement by a...Ch. 7 - Use the information In Example 7.8, but use a...Ch. 7 - Use the information in Example 7.9, but change the...Ch. 7 - Based on data from the National Health Survey,...
Ch. 7 - According to Boeing data, the 757 airliner carries...Ch. 7 - In a city, 46 percent of the population favor the...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - True or False: only the sums of normal...Ch. 7 - In order for the sums of a distribution to...Ch. 7 - What three things must you know about a...Ch. 7 - An unknown distribution has a mean of 25 and a...Ch. 7 - An unknown distribution has a mean of 19 and a...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use (he following information to answer the next...Ch. 7 - Use (he following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Previously; De Anza statistics students estimated...Ch. 7 - Suppose that the distance of fly balls hit to the...Ch. 7 - According to the Internal Revenue Service, the...Ch. 7 - Suppose that a category of world-class runners are...Ch. 7 - The length of songs In a collectors [runes album...Ch. 7 - In 1940 the average size of a U.S. farm was 174...Ch. 7 - Determine which of the following are true and...Ch. 7 - The percent of fat calories that a pet-son m...Ch. 7 - The distribution of income in son Third World...Ch. 7 - Which of the following is NOT TRUE about the...Ch. 7 - The cost of unleaded gasoline in the Bay Area once...Ch. 7 - Which of the following is NOT TRUE about the...Ch. 7 - Suppose that the duration of a particular type of...Ch. 7 - Suppose that the weight of open boxes of cereal in...Ch. 7 - Salaries for teachers in a particular elementary...Ch. 7 - The attention span of a two-year-old is...Ch. 7 - The closing stock prices of 35 U.S. semiconductor...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following information to answer the next...Ch. 7 - Use the following (0 answer the next two...Ch. 7 - Use the following (0 answer the next two...Ch. 7 - Suppose In a local Kindergarten through 12th grade...Ch. 7 - Four friends, Janice. Barbara, Kathy and Roberta,...Ch. 7 - XN (60, 9). Suppose that you form random samples...Ch. 7 - Suppose that the length of research papers is...Ch. 7 - Salaries for teachers In a particular elementary...Ch. 7 - The average length of a maternity stay In a U.S....Ch. 7 - For each problem. wherever possible, provide...Ch. 7 - Men have an average weight of 172 pounds with a...Ch. 7 - M&M candies large candy bags have a claimed net...Ch. 7 - The Screw Right Company claims their 34 inch...Ch. 7 - Your company has a contract to perform preventive...Ch. 7 - A typical adult has an average IQ score of 105...Ch. 7 - Certain coins have an average weight of 5.201...
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