Elementary Statistics (Text Only)
2nd Edition
ISBN: 9780077836351
Author: Author
Publisher: McGraw Hill
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Chapter 8.4, Problem 12E
Construct a 99% confidence interval for the population standard deviation
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very time you conduct a hypothesis test, there are four possible outcomes of your decision to reject or not reject the null hypothesis: (1) You don’t reject the null hypothesis when it is true, (2) you reject the null hypothesis when it is true, (3) you don’t reject the null hypothesis when it is false, and (4) you reject the null hypothesis when it is false.
Consider the following analogy: You are an airport security screener. For every passenger who passes through your security checkpoint, you must decide whether to select the passenger for further screening based on your assessment of whether he or she is carrying a weapon. Suppose your null hypothesis is that the passenger has a weapon. As in hypothesis testing, there are four possible outcomes of your decision: (1) You select the passenger for further inspection when the passenger has a weapon, (2) you allow the passenger to board her flight when the passenger has a weapon, (3) you select the passenger for further inspection when…
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Ch 6 Sec 4 Homework
Question 4 of 4 (1 point) | Question Attempt: 2 of Unlimited
✓ 2
✓ 3
= 4
Stress at work: In a poll conducted by the General Social Survey, 81% of respondents said that their jobs were sometimes or always stressful. Two hundred
workers are chosen at random. Use the TI-84 Plus calculator as needed. Round your answer to at least four decimal places.
(a) Approximate the probability that 155 or fewer workers find their jobs stressful.
(b) Approximate the probability that more than 145 workers find their jobs stressful.
(c) Approximate the probability that the number of workers who find their jobs stressful is between 154 and 172 inclusive.
Part 1 of 3
The probability that 155 or fewer workers find their jobs stressful is 0.1207
Part 2 of 3
bility that more than 145 workers find their jobs…
A case-control (or retrospective) study was conducted to investigate a relationship between the colors of helmets worn by motorcycle drivers and whether they are injured or killed in a crash. Results are given in the accompanying table. Using a 0.01
significance level, test the claim that injuries are independent of helmet color.
Color of Helmet
Black
White
Yellow
Red
Blue
Controls (not injured)
499
373
32
159
79
Cases (injured
221
108
8
66
38
or killed)
Click here to view the chi-square distribution table.
Chi-square distribution table
Area to the Right of the Critical Value
Degrees of
Freedom
0.995
0.99
0.975
0.95
0.90
0.10
0.05
0.025
0.01
0.005
C. Ho: Injuries and neimet color are dependent
H₁: Injuries and helmet color are independent
D. Ho: Whether a crash occurs and helmet color are dependent
1
0.001
0.004
0.016
2.706
3.841
5.024
6.635
7.879
2
0.010
0.020
0.051
0.103
0.211
4.605
5.991
7.378
9.210
10.597
3
0.072
0.115
0.216
0.352
0.584
6.251
7.815
9.348
11.345
12.838
4
0.207
0.297…
Chapter 8 Solutions
Elementary Statistics (Text Only)
Ch. 8.1 - In Exercises 17—20, fill in each blank with the...Ch. 8.1 - Prob. 18ECh. 8.1 - In Exercises 17—20, fill in each blank with the...Ch. 8.1 - In Exercises 17-20, fill in each blank with the...Ch. 8.1 - In Exercises 21-24, determine whether the...Ch. 8.1 - In Exercises 21-24, determine whether the...Ch. 8.1 - In Exercises 21-24, determine whether the...Ch. 8.1 - Prob. 24ECh. 8.1 - In Exercises 25-28, find the critical value z/2...Ch. 8.1 - In Exercises 25-28, find the critical value z/2...
Ch. 8.1 - In Exercises 25-28, find the critical value z/2...Ch. 8.1 - Prob. 28ECh. 8.1 - In Exercises 29-32, find the levels of the...Ch. 8.1 - In Exercises 29-32, find the levels of the...Ch. 8.1 - In Exercises 29-32, find the levels of the...Ch. 8.1 - In Exercises 29-32, find the levels of the...Ch. 8.1 - A sample of size n=49 is drawn from a population...Ch. 8.1 - Prob. 34ECh. 8.1 - A sample of size n=32 is drawn from a population...Ch. 8.1 - A sample of size n=64 is drawn from a population...Ch. 8.1 - A sample of sue n=10 is drawn from a normal...Ch. 8.1 - Prob. 38ECh. 8.1 - A population has standard deviation 21.3. How...Ch. 8.1 - Prob. 40ECh. 8.1 - A population has standard deviation =12.7 How...Ch. 8.1 - Prob. 42ECh. 8.1 - SAT scores: A college admissions officer takes a...Ch. 8.1 - Prob. 44ECh. 8.1 - Babies: According to the National Health...Ch. 8.1 - Watch your cholesterol: A sample of 314 patients...Ch. 8.1 - How smart is your phone? A random sample of 11...Ch. 8.1 - Stock prices: The Standard and Poors (S=50....Ch. 8.1 - High energy: A random sample of energy drinks had...Ch. 8.1 - Lets shake on it: A random sample of 12-ounce...Ch. 8.1 - Lifetime of electronics: In a simple random sample...Ch. 8.1 - Efficient manufacturing: Efficiency experts study...Ch. 8.1 - Prob. 53ECh. 8.1 - Prob. 54ECh. 8.1 - Prob. 55ECh. 8.1 - Prob. 56ECh. 8.1 - Prob. 57ECh. 8.1 - Prob. 58ECh. 8.1 - Prob. 59ECh. 8.1 - Dont construct a confidence interval: A college...Ch. 8.1 - Prob. 61ECh. 8.1 - Prob. 62ECh. 8.1 - Prob. 63ECh. 8.1 - Prob. 64ECh. 8.1 - Prob. 65ECh. 8.1 - Prob. 66ECh. 8.1 - Prob. 67ECh. 8.1 - Prob. 68ECh. 8.2 - In Exercises 7 and 8, fill in each blank with the...Ch. 8.2 - Prob. 8ECh. 8.2 - Prob. 9ECh. 8.2 - Prob. 10ECh. 8.2 - Find the critical value t/2 needed to construct a...Ch. 8.2 - Find the critical value t/2 needed to construct a...Ch. 8.2 - A sample of size n=22 is drawn from a normal...Ch. 8.2 - A sample of size n=12 is drawn from a normal...Ch. 8.2 - A sample of size n=12 is drawn. Find the critical...Ch. 8.2 - A sample of size n=15 has sample mean x=2.1 and...Ch. 8.2 - A sample of size n=44 has sample mean x=56.9 and...Ch. 8.2 - A sample of size n=89 has sample mean x=87.2 and...Ch. 8.2 - A sample of size n=35 has sample mean x=34.85 and...Ch. 8.2 - Online courses: A sample of 263 students who were...Ch. 8.2 - Get an education: The General Social Survey asked...Ch. 8.2 - Fake Twitter followers: Many celebrities and...Ch. 8.2 - Prob. 24ECh. 8.2 - Hip surgery: In a sample of 123 hip surgeries of a...Ch. 8.2 - Sound it out: Phonics is an instructional method...Ch. 8.2 - Software instruction: A hybrid course is one that...Ch. 8.2 - Baby talk: In a sample of 77 children, the mean...Ch. 8.2 - Baby weights: Following are weights: m pounds: of...Ch. 8.2 - Prob. 30ECh. 8.2 - Eat your spinach: Six measurements were made of...Ch. 8.2 - Mortgage rates: Following are interest rates...Ch. 8.2 - Hi-def: Following are prices of a random sample of...Ch. 8.2 - Big salary for the boss: Following is the total...Ch. 8.2 - Prob. 35ECh. 8.2 - Prob. 36ECh. 8.2 - Eat your kale: Kale is a type of cabbage commonly...Ch. 8.2 - Prob. 38ECh. 8.2 - Prob. 39ECh. 8.2 - Prob. 40ECh. 8.2 - Dont construct a confidence interval: There have...Ch. 8.2 - Dont construct a confidence interval: As of July...Ch. 8.2 - Prob. 43ECh. 8.2 - Prob. 44ECh. 8.2 - Prob. 45ECh. 8.2 - Prob. 46ECh. 8.2 - Prob. 47ECh. 8.3 - In Exercises 7 and 8, fill in each blank with the...Ch. 8.3 - In Exercises 7 and 8, fill in each blank with the...Ch. 8.3 - In Exercises 9 and 10, determine whether the...Ch. 8.3 - Prob. 10ECh. 8.3 - Prob. 11ECh. 8.3 - In Exercises 11-14, find the point estimate, the...Ch. 8.3 - In Exercises 11-14, find the point estimate, the...Ch. 8.3 - In Exercises 11-14, find the point estimate, the...Ch. 8.3 - In Exercises 15-18, use the given data to...Ch. 8.3 - In Exercises 15-18, use the given data to...Ch. 8.3 - In Exercises 15-18, use the given data to...Ch. 8.3 - In Exercises 15-18, use the given data to...Ch. 8.3 - Smart phone: Among 238 cell phone owners aged...Ch. 8.3 - Working at home: According to the U.S. Census...Ch. 8.3 - Sleep apnea: Sleep apnea is a disorder in which...Ch. 8.3 - Internet service: An Internet service provider...Ch. 8.3 - Volunteering: The General Social Survey asked 1294...Ch. 8.3 - SAT scores: A college admissions officer sampled...Ch. 8.3 - WOW: In the computer game World of Warcraft. Some...Ch. 8.3 - Prob. 26ECh. 8.3 - Call me: A sociologist wants to construct a 95%...Ch. 8.3 - Reading proficiency: An educator wants to...Ch. 8.3 - Surgical complications: A medical researcher wants...Ch. 8.3 - Hows the economy? A pollster wants to construct a...Ch. 8.3 - Changing jobs: A sociologist sampled 200 people...Ch. 8.3 - Prob. 32ECh. 8.3 - Prob. 33ECh. 8.3 - Prob. 34ECh. 8.3 - Prob. 35ECh. 8.3 - Prob. 36ECh. 8.3 - Prob. 37ECh. 8.3 - Prob. 38ECh. 8.3 - Prob. 39ECh. 8.3 - Dont construct a confidence interval: At the end...Ch. 8.3 - Prob. 41ECh. 8.3 - Prob. 42ECh. 8.3 - Wilsons interval: The small-sample method for...Ch. 8.4 - In Exercises 5 and 6, fill in each blank with the...Ch. 8.4 - In Exercises 5 and 6, fill in each blank with the...Ch. 8.4 - In Exercises 7 and 8, determine whether the...Ch. 8.4 - Prob. 8ECh. 8.4 - Find the critical values for a 95% confidence...Ch. 8.4 - Find the critical values for a 99% confidence...Ch. 8.4 - Construct a 95% confidence interval for the...Ch. 8.4 - Construct a 99% confidence interval for the...Ch. 8.4 - SAT scores: Scores on the math SAT are normally...Ch. 8.4 - IQ scores: Scores on an IQ test are normally...Ch. 8.4 - Baby weights: are weights of 12 two-month-old baby...Ch. 8.4 - Eat your cereal: Boxes of cereal are labeled as...Ch. 8.4 - Eat your spinach: Six measurements were made of...Ch. 8.4 - Mortgage rates: Following are interest rates...Ch. 8.4 - Prob. 19ECh. 8.4 - Using the normal approximation: Refer to Exercise...Ch. 8.4 - Prob. 21ECh. 8.4 - More accuracy: Refer to Exercise 19. Use the more...Ch. 8.4 - Prob. 23ECh. 8.5 - In Exercises 5-12, state which type of parameter...Ch. 8.5 - In Exercises 5-12, state which type of parameter...Ch. 8.5 - In Exercises 5-12, state which type of parameter...Ch. 8.5 - Prob. 8ECh. 8.5 - In Exercises 5-12, state which type of parameter...Ch. 8.5 - In Exercises 5-12, state which type of parameter...Ch. 8.5 - In Exercises 5-12, state which type of parameter...Ch. 8.5 - In Exercises 5-12, state which type of parameter...Ch. 8.5 - Prob. 13ECh. 8.5 - Ages of students: A simple random sample of 100...Ch. 8.5 - Calories in bread: Following are the numbers of...Ch. 8.5 - Credit card debt: In a survey of 1118 U.S. adults...Ch. 8.5 - Windy place: Mt. Washington, New Hampshire, is one...Ch. 8.5 - An apple a day: Following are the numbers of grams...Ch. 8.5 - Pneumonia: In a simple random sample of 1500...Ch. 8.5 - Prob. 20ECh. 8 - Define the following terms: Point estimate...Ch. 8 - Prob. 2CQCh. 8 - Prob. 3CQCh. 8 - Construct a confidence interval for the population...Ch. 8 - Prob. 5CQCh. 8 - Prob. 6CQCh. 8 - Prob. 7CQCh. 8 - Prob. 8CQCh. 8 - Prob. 9CQCh. 8 - Prob. 10CQCh. 8 - Prob. 11CQCh. 8 - Prob. 12CQCh. 8 - Prob. 13CQCh. 8 - Prob. 14CQCh. 8 - Prob. 15CQCh. 8 - Prob. 1RECh. 8 - Prob. 2RECh. 8 - Cost of environmental restoration: In a survey of...Ch. 8 - Prob. 4RECh. 8 - Prob. 5RECh. 8 - Contaminated water: Polychlorinated biphenyls...Ch. 8 - Prob. 7RECh. 8 - Cost of repairs: A sample of eight repair records...Ch. 8 - Cost of repairs: Refer to Exercise 8. Assume the...Ch. 8 - Prob. 10RECh. 8 - Prob. 11RECh. 8 - Sleep time: In a sample of 87 young adults, the...Ch. 8 - Leaking tanks: Leakage from underground fuel tanks...Ch. 8 - Prob. 14RECh. 8 - Prob. 15RECh. 8 - Prob. 1WAICh. 8 - What factors can you think of that may affect the...Ch. 8 - Prob. 3WAICh. 8 - Prob. 4WAICh. 8 - Prob. 5WAICh. 8 - When constructing a confidence interval for , how...Ch. 8 - Prob. 7WAICh. 8 - Prob. 1CSCh. 8 - Prob. 2CSCh. 8 - Prob. 3CSCh. 8 - Prob. 4CSCh. 8 - Prob. 5CS
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- Conduct the hypothesis test and provide the test statistic and the critical value, and state the conclusion. A person drilled a hole in a die and filled it with a lead weight, then proceeded to roll it 200 times. Here are the observed frequencies for the outcomes of 1, 2, 3, 4, 5, and 6, respectively: 28, 32, 46, 39, 29, 26. Use a 0.025 significance level to test the claim that the outcomes are not equally likely. Does it appear that the loaded die behaves differently than a fair die? Click here to view the chi-square distribution table. The test statistic is (Round to three decimal places as needed.) Chi-square distribution table Area to the Right of the Critical Value Degrees of Freedom 0.995 0.99 0.975 0.95 0.90 0.10 0.05 0.025 0.01 0.005 1 0.001 0.004 0.016 2.706 3.841 5.024 6.635 2 0.010 0.020 0.051 0.103 0.211 4.605 5.991 7.378 9.210 7.879 10.597 3 0.072 0.115 0.216 0.352 0.584 6.251 7.815 9.348 11.345 12.838 4 0.207 0.297 0.484 0.711 1.064 7.779 9.488 11.143 13.277 14.860 5…arrow_forwardThe online clothing retailer e-Parel is conducting a study to estimate the average size of the orders placed by visitors to its website. The project manager desires a $60 bound on the error of estimation at 90% confidence. The population standard deviation is unknown, and a “best guess” of $175 is used as the planning value for σ. Use the Distributions tool to help you answer the questions that follow. 0123 Select a Distribution The z-value for a 90% confidence interval of the population mean is . In order to satisfy the requirement of a $60 bound on the error of estimation, a sample size no smaller than is needed.arrow_forwardA local electronics store just received a shipment of 620 HDMI cables. The manager wants to estimate the number of defective HDMI cables in the shipment. Rather than checking every HDMI cable, the manager plans to take a simple random sample of size 62 in order to estimate the proportion of defective HDMI cables in the shipment. If the sample proportion of defective HDMI cables, p̂p̂, is greater than 0.0323 (there are more than two defective HDMI cables in the sample), the manager will file a complaint and request a new shipment. Suppose that the true proportion of defective HDMI cables in the shipment is approximately p = 0.02. What is the expected value of the sample proportion? E(Pˆ)E(P^)= Since the sample is to be drawn from a finite population, and since the sample is 5% of the population size, the finite population correction factor needed when you calculate the standard deviation of the sampling distribution. What is the standard deviation of the…arrow_forward
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