An Introduction to Statistical Methods and Data Analysis
7th Edition
ISBN: 9781305269477
Author: R. Lyman Ott, Micheal T. Longnecker
Publisher: Cengage Learning
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Textbook Question
Chapter 5.12, Problem 6E
Refer to Exercise 5.5. The engineer in charge of the coffee manufacturing process examines the confidence intervals for the mean caffeine content calculated over the past several weeks and is concerned that the intervals are too wide to be of any practical use. That is, they are not providing a very precise estimate of μ.
- a. What would happen to the width of the confidence intervals if the level of confidence of each interval is increased from 95% to 99%?
- b. What would happen to the width of the confidence intervals if the number of samples per hour was increased from 50 to 100?
5.5 A company that manufacturers coffee for use in commercial machines monitors the caffeine content in its coffee. The company selects 50 samples of coffee every hour from its production line and determines the caffeine content. From historical data, the caffeine content (in milligrams, mg) is known to have a
- a. Identify the population about which inferences can be made from the sample data.
- b. Calculate a 95% confidence interval for the mean caffeine content μ of the coffee produced during the hour in which the 50 samples were selected.
- c. Explain to the CEO of the company in nonstatistical language the interpretation of the constructed confidence interval.
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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
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Change Column(s)
Generate 1 Sample
Generate 10 Samples
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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
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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 5 Solutions
An Introduction to Statistical Methods and Data Analysis
Ch. 5.12 - The county government in a city that is dominated...Ch. 5.12 - In the research study on percentage of calories...Ch. 5.12 - Face masks used by firefighters often fail by...Ch. 5.12 - Refer to Exercise 5.3. Describe a process to...Ch. 5.12 - A company that manufacturers coffee for use in...Ch. 5.12 - Refer to Exercise 5.5. The engineer in charge of...Ch. 5.12 - Refer to Exercise 5.5. Because the company is...Ch. 5.12 - As part of the recruitment of new businesses, the...Ch. 5.12 - A program to reduce recidivism has been in effect...Ch. 5.12 - The susceptibility of the root stocks of a variety...
Ch. 5.12 - Prob. 11ECh. 5.12 - In any given situation, if the level of confidence...Ch. 5.12 - A biologist wishes to estimate the effect of an...Ch. 5.12 - Refer to Exercise 5.14. Suppose the mayors staff...Ch. 5.12 - Refer to Exercise 5.14. Suppose the mayors staff...Ch. 5.12 - A study is designed to test the hypotheses H0: ...Ch. 5.12 - Refer to Exercise 5.16. Graph the power curve for...Ch. 5.12 - A study was conducted of 90 adult male patients...Ch. 5.12 - Prob. 22ECh. 5.12 - A national agency sets recommended daily dietary...Ch. 5.12 - To evaluate the success of a 1-year experimental...Ch. 5.12 - Refer to Exercise 5.24. Suppose a random sample of...Ch. 5.12 - The administrator of a nursing home would like to...Ch. 5.12 - The vulnerability of inshore environments to...Ch. 5.12 - The RD department of a paint company has developed...Ch. 5.12 - Prob. 29ECh. 5.12 - A concern to public health officials is whether a...Ch. 5.12 - Prob. 31ECh. 5.12 - Prob. 32ECh. 5.12 - Prob. 33ECh. 5.12 - Provide the rejection region based on a t-test...Ch. 5.12 - A study was designed to evaluate whether the...Ch. 5.12 -
The ability to read rapidly and simultaneously...Ch. 5.12 - Refer to Exercise 5.36. Using the reading...Ch. 5.12 -
Refer to Exercise 5.36.
Does there appear to be a...Ch. 5.12 - A consumer testing agency wants to evaluate the...Ch. 5.12 -
Refer to Exercise 5.39.
Does the normality of the...Ch. 5.12 - The amount of sewage and industrial pollutants...Ch. 5.12 - A dealer in recycled paper places empty trailers...Ch. 5.12 - Prob. 47ECh. 5.12 - Prob. 48ECh. 5.12 - Prob. 49ECh. 5.12 - Prob. 50ECh. 5.12 - Prob. 51ECh. 5.12 - Prob. 52ECh. 5.12 - Prob. 53ECh. 5.12 - Prob. 54ECh. 5.12 - Prob. 55ECh. 5.12 - Prob. 56ECh. 5.12 - Prob. 57SECh. 5.12 - The concentration of mercury in a lake has been...Ch. 5.12 -
In a standard dissolution test for tablets of a...Ch. 5.12 - Prob. 60SECh. 5.12 -
Over the past 5 years, the mean time for a...Ch. 5.12 - If a new process for mining copper is to be put...Ch. 5.12 - Prob. 63SECh. 5.12 - Prob. 64SECh. 5.12 - Prob. 65SECh. 5.12 - Prob. 66SECh. 5.12 - Prob. 67SECh. 5.12 - Prob. 68SECh. 5.12 - Prob. 69SECh. 5.12 - Prob. 70SECh. 5.12 - Prob. 71SECh. 5.12 - Prob. 73SECh. 5.12 - Prob. 74SECh. 5.12 - Prob. 75SECh. 5.12 - Prob. 76SE
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