Quiz 4_ Attempt review _ Courses 2023-2024

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3/28/24, 1:12 PM Quiz 4: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1622633&cmid=955464 1/6 Started on Sunday, February 4, 2024, 7:15 PM State Finished Completed on Sunday, February 4, 2024, 7:42 PM Time taken 26 mins 42 secs Points 3.25/10.00 Grade 32.50 out of 100.00 Question 1 Incorrect 0.00 points out of 1.00 55% of all internet sites are in English. If we randomly select 21 websites, what do we know about the distribution of the sample proportion of English language websites? a. The distribution will be symmetric but not Normal. b. We can determine that the distribution of the parent population will be approximately Normal, but not the sampling distribution .  c. We CANNOT determine that the distribution will be approximately Normal. d. The CAN determine that the distribution will be approximately Normal. Your answer is incorrect. The correct answer is: We CANNOT determine that the distribution will be approximately Normal.

3/28/24, 1:12 PM Quiz 4: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1622633&cmid=955464 2/6 Question 2 Partially correct 0.25 points out of 1.00 Question 3 Incorrect 0.00 points out of 1.00 All G-rated, animated feature films released between 1937 and 1997 by 5 major production companies (Walt Disney Co, MGM/United Artists, Warner Brothers Studios, Universal Studios, and 20th Century Fox) that were available on videotape were reviewed for episodes of tobacco and alcohol use. 68% displayed at least 1 episode of tobacco or alcohol use. A random sample of 20 G-rated, animated films are selected. Which of the following statements are true? ( select all that are true) Select one or more: a. The mean of all sample proportions of 20 films is equal to 0.68  b. We can approximate the distribution of the sample proportion with a Normal distribution whose mean is 17  c. We can approximate the distribution of the sample proportion with a Normal distribution whose mean is 0.68 d. The sample proportion of these 20 films is equal to 0.68 e. We cannot approximate the distribution of the sample proportion with a Normal distribution f. The mean of all sample proportions of 20 films is equal to 17 Your answer is partially correct. You have correctly selected 1. The correct answers are: The mean of all sample proportions of 20 films is equal to 0.68, We cannot approximate the distribution of the sample proportion with a Normal distribution According to a recent study, 32% of working adults have a short commute to their jobs. In a random sample of 60 working adults, how much does the sample proportion of working adults with a short commute vary (i.e. what is the standard error)? Round your answer to 4 decimal places. Answer: 0.0506  The correct answer is: 0.0602

3/28/24, 1:12 PM Quiz 4: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1622633&cmid=955464 3/6 Question 4 Incorrect 0.00 points out of 1.00 Question 5 Incorrect 0.00 points out of 1.00 The results of a recent survey indicate that when grilling, 59% of all households in the US use a gas grill. Assume you randomly select 85 households. Of 85 randomly selected households in the US, find the expected number of households that use a gas grill. Answer: 44.25  The correct answer is: 50.15 The results of a recent survey indicate that when grilling, 59% of all households in the US use a gas grill. Assume you randomly select 100 households. Find the probability that between 30 and 60 households use a gas grill. (Round your answer to 3 decimal places) Answer: 0.581  The correct answer is: 0.618

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3/28/24, 1:12 PM Quiz 4: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1622633&cmid=955464 4/6 Question 6 Correct 1.00 points out of 1.00 Question 7 Not answered Points out of 1.00 The United States Postal Service (USPS) delivered 32% of all packages shipped in the US in the year 2022. In 2015, USPS delivered 40% of all packages. Which of the following statements about the standard deviation of the sample proportion (that is, ) are correct? Select all that apply. a. The standard deviation of the sample proportion for a sample of 100 packages in 2022 will be smaller than for a sample of 400 packages in 2022. b. If we randomly select 100 packages from 2022 and 100 package from 2015, the standard deviation of the sample proportion will be larger for 2015.  c. For the standard deviation of the sample proportion for 2022 to be equal to that in 2015, the sample sizes must be the same. d. The standard deviation of the sample proportion of packages shipped by USPS for 2022 is smaller than the standard deviation of the parent population.  Your answer is correct. The correct answers are: If we randomly select 100 packages from 2022 and 100 package from 2015, the standard deviation of the sample proportion will be larger for 2015. , The standard deviation of the sample proportion of packages shipped by USPS for 2022 is smaller than the standard deviation of the parent population. The results of a recent survey indicate that when grilling, 59% of all households in the US use a gas grill. Assume you randomly select 100 households. Find the probability that at least 60 households use a gas grill. (Round your answer to 3 decimal places) Answer:  The correct answer is: 0.462

3/28/24, 1:12 PM Quiz 4: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1622633&cmid=955464 5/6 Question 8 Correct 1.00 points out of 1.00 Question 9 Incorrect 0.00 points out of 1.00 In America, 53% of people leave a tip for their hairdresser. Suppose a random sample of 300 Americans is selected and 65% of those 300 leave a tip for their hairdresser. Which of the following is true? a. The mean of the sampling distribution for the sample proportion with n = 100 is 0.65. b. The mean of the sampling distribution for the sample proportion with n = 100 is 159. c. The mean of the sampling distribution for the sample proportion with n = 100 is 0.53.  d. The mean of the sampling distribution for the sample proportion with n = 100 depends on whether the distribution is Normal. e. The mean of the sampling distribution for the sample proportion with n = 100 is 195. Your answer is correct. The correct answer is: The mean of the sampling distribution for the sample proportion with n = 100 is 0.53. Eighteen percent of married couples in U.S. had a destination wedding. Linda is a wedding planner looking to work on destination weddings. She meets with prospective clients until she finds 10 planning destination weddings. The number of prospective clients she meets with is recorded. Are the conditions for a binomial experiment met? Select all that apply. Select one or more: a. No - the random variable does not count successes b. No - there is not a fixed number of trials c. No - the distribution is not bell-shaped d. No - there are not two possible outcomes e. Yes - all conditions are met  Your answer is incorrect. The correct answers are: No - the random variable does not count successes, No - there is not a fixed number of trials

3/28/24, 1:12 PM Quiz 4: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1622633&cmid=955464 6/6 Question 10 Correct 1.00 points out of 1.00 About 10% of workers (ages 16 and older) in the United States commute to their jobs by carpooling. In a sample of 146 workers in the US, would it be unusual if 20 carpooled to work? Select one: a. Yes, because the probability of 20 carpoolers is less than 5% b. No, because the probability of 20 or more carpoolers is greater than 5%.  c. No, because 20 is within 2 standard deviations of the mean number of carpoolers. d. Yes, because 20 is beyond 2 standard deviations of the mean number of carpoolers. e. No, because this is only a sample and outcomes from samples vary. f. Yes, because 10% of 146 is 15 carpoolers. So 20 is too big. Your answer is correct. The correct answers are: No, because the probability of 20 or more carpoolers is greater than 5%., No, because 20 is within 2 standard deviations of the mean number of carpoolers. ◄ ICA 4 Jump to... Week 4 Recap Slides (SHORT!) ►

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