Statistics: The Art and Science of Learning from Data (4th Edition)
4th Edition
ISBN: 9780321997838
Author: Alan Agresti, Christine A. Franklin, Bernhard Klingenberg
Publisher: PEARSON
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Chapter 4, Problem 70CP
a.
To determine
Find the conditional proportions of the potential confounder (amount of exercise) for each treatment group.
Identify whether they are similar or not.
b.
To determine
Explain whether the randomization process did have balanced treatment groups in terms of the potential confounder or not.
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Example 4 (Part 2) We can use Statkey to take 50 different random samples of size 20 each, find the mean of
each sample, and compute a confidence interval for each one. The graph of the sampling distribution of the means
is on the left below, and that of the 50 confidence intervals is on the right.
1. What does each dot on the left hand dotplot represent?
StatKey Sampling Distribution for a Mean
Percent with Internet Access (Countries) ▾
Show Data Table Edit Data
Choose samples of size n =
20
Upload File
Change Column(s)
Generate 1 Sample
Generate 10 Samples
Generate 100 Samples
Generate 1000 Samples
Reset Plot
Sampling Dotplot of Mean
Left Tail Two-Tail Right Tail
60
50
40
40
30
20
20
10
samples = 50
mean = 41.626
std. error = 5.089
:
.:
:
::
0
25
30
35
40
45
50
55
60
41.626
Data Plots
Confidence Intervals
95%->
Confidence Intervals
Coverage
48/50 = 96%
20
40
60
80
2. Circle the confidence intervals that failed to capture the true mean.
3. Circle the sample means that produced those…
Example 4 (Part 1) One of the datasets in the Lock book
contains information about 215 countries of the world. One
of the variables is the percentage of people in the country
who have access to the internet. We have data for 203 of
those countries. The plot on the right shows a dotplot of
the data.
1. What are the cases?
Population
n = 203, mean = 43.024
median = 43.5, stdev = 29.259
20
2. What does each dot on the dotplot represent?
15
10
5
20
40
43.024
60
80
3. What type of data is do we collect from the cases, quantitative or categorical?
Let x be a random variable that represents the percentage of successful free throws a professional basketball player makes in a season. Let y be a random variable that represents the percentage of successful field goals a professional basketball player makes in a season. A random sample of n =6 professional basketball players gave the following information.
x
63
79
70
80
84
87
y
46
49
45
55
57
58
Find Se. Round your answer to three decimal places.
Chapter 4 Solutions
Statistics: The Art and Science of Learning from Data (4th Edition)
Ch. 4.1 - Cell phones Consider the cell phone Study 3...Ch. 4.1 - High blood pressure and binge drinking Many...Ch. 4.1 - Low-fat versus low-carb diet? One hundred...Ch. 4.1 - Experiments versus observational studies When...Ch. 4.1 - School testing for drugs Example 3 discussed a...Ch. 4.1 - Hormone therapy and heart disease Since 1976 the...Ch. 4.1 - Speaking foreign languages A 2014 study...Ch. 4.1 - Breast-cancer screening A study published in 2010...Ch. 4.1 - Experiment or observe? Explain whether an...Ch. 4.1 - Baseball under a full moon During a baseball game...
Ch. 4.1 - Seat belt anecdote Andy once heard about a car...Ch. 4.1 - Poker as a profession? Tonys mother is extremely...Ch. 4.1 - Whats more to blame for obesity? In a study...Ch. 4.1 - Census every 10 years? A nationwide census is...Ch. 4.2 - Choosing officers A campus club consists of five...Ch. 4.2 - Simple random sample of students In Example 4, a...Ch. 4.2 - Auditing accountsapp Use an app or computer...Ch. 4.2 - Sampling from a directory A local telephone...Ch. 4.2 - Bias due to perceived race A political scientist...Ch. 4.2 - Confederates Some southern states in the United...Ch. 4.2 - Instructor ratings The website...Ch. 4.2 - Job trends The 20132014 Recruiting Trends report,...Ch. 4.2 - Gun control More than 75% of Americans answer yes...Ch. 4.2 - Violent video games and family closeness A recent...Ch. 4.2 - Fracking The journal Energy Policy (2014, 65:...Ch. 4.2 - Teens buying alcohol over Internet In August 2006,...Ch. 4.2 - Cheating spouses and bias In a survey conducted by...Ch. 4.2 - Online dating A story titled Personals, Sex Sites...Ch. 4.2 - Identify the bias A newspaper designs a survey to...Ch. 4.2 - Types of bias Give an example of a survey that...Ch. 4.3 - Smoking affects lung cancer? You would like to...Ch. 4.3 - Never leave home without duct tape There have been...Ch. 4.3 - More duct tape In a follow-up study, 103 patients...Ch. 4.3 - Vitamin B A New York Times article (March 13,...Ch. 4.3 - Facebook study During the one-week period of...Ch. 4.3 - Science faculty selection of grad students In an...Ch. 4.3 - Pain reduction medication Consider an experiment...Ch. 4.3 - Pain reduction medication, continued Consider the...Ch. 4.3 - Pain reduction medication, yet again Revisit the...Ch. 4.3 - Colds and vitamin C For some time there has been...Ch. 4.3 - Reducing high blood pressure A pharmaceutical...Ch. 4.4 - Student loan debt A researcher wants to compare...Ch. 4.4 - Club officers again In Exercise 4.15, two officers...Ch. 4.4 - Security awareness training Of 400 employees at a...Ch. 4.4 - Prob. 45PBCh. 4.4 - Prob. 46PBCh. 4.4 - Prob. 47PBCh. 4.4 - Prob. 48PBCh. 4.4 - Prob. 49PBCh. 4.4 - Prob. 50PBCh. 4.4 - Prob. 51PBCh. 4.4 - Prob. 52PBCh. 4.4 - Effect of partner smoking in smoking cessation...Ch. 4 - Cell phones If you want to conduct a study with...Ch. 4 - Observational versus experimental study Without...Ch. 4 - Unethical experimentation Give an example of a...Ch. 4 - Spinal fluid proteins and Alzheimers A research...Ch. 4 - Fear of asbestos Your friend reads about a study...Ch. 4 - NCAA mens basketball poll The last four teams of...Ch. 4 - Sampling your fellow students You are assigned to...Ch. 4 - Prob. 61CPCh. 4 - Comparing female and male students You plan to...Ch. 4 - Football discipline A large southern university...Ch. 4 - Prob. 64CPCh. 4 - Voluntary sports polls In 2014, the Pittsburgh...Ch. 4 - Video games mindless? Playing video games not so...Ch. 4 - Physicians health study Read about the first...Ch. 4 - Aspirin prevents heart attacks? During the 1980s...Ch. 4 - Prob. 69CPCh. 4 - Prob. 70CPCh. 4 - Prob. 71CPCh. 4 - Bupropion and nicotine patch study results The...Ch. 4 - Prefer Coke or Pepsi? You want to conduct an...Ch. 4 - Prob. 74CPCh. 4 - Samples not equally likely in a cluster sample? In...Ch. 4 - Nursing homes You plan to sample residents of...Ch. 4 - Multistage health survey A researcher wants to...Ch. 4 - Hazing Hazing within college fraternities is a...Ch. 4 - Prob. 79CPCh. 4 - Twins and breast cancer Excessive cumulative...Ch. 4 - Judging sampling design In each of the following...Ch. 4 - Prob. 87CPCh. 4 - Age for legal alcohol You want to investigate the...Ch. 4 - Prob. 89CPCh. 4 - Prob. 90CPCh. 4 - Issues in clinical trials A randomized clinical...Ch. 4 - Prob. 92CPCh. 4 - Prob. 93CPCh. 4 - Prob. 94CPCh. 4 - Prob. 95CPCh. 4 - Prob. 96CPCh. 4 - For Exercises 4.974.103, select the best response....Ch. 4 - Prob. 98CPCh. 4 - For Exercises 4.974.103, select the best response....Ch. 4 - For Exercises 4.974.103, select the best response....Ch. 4 - Prob. 101CPCh. 4 - For Exercises 4.974.103, select the best response....Ch. 4 - Prob. 103CPCh. 4 - Systematic sampling A researcher wants to select...Ch. 4 - Prob. 106CPCh. 4 - Prob. 107CP
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