31 stats students were asked how long it took them to finish the midterm exam. The...
31 stats students were asked how long it took them to finish the midterm exam. The sample mean was found to be 192 minutes and the sample standard deviation was 7 minutes. Create a 99% confidence interval for the population mean.
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31 stats students were asked how long it took them to finish the
midterm exam. The...
A random sample of 13 students were asked how long it took them to complete a...
A random sample of 13 students were asked how long it took them to complete a certain exam. The mean length of time was 105.5 minutes, with a standard deviation of 66.7 minutes. Find the lower bound of the 90% confidence interval for the true mean length of time it would take for all students to complete the exam. Round to one decimal place (for example: 108.1). Write only a number as your answer. Do not write any units.
Students in an introductory statistics class were asked to report the age of their mothers when...
Students in an introductory statistics class were asked to report the age of their mothers when they were born. Summary statistics include Sample size: 28 students Sample mean: 29.643 years Sample standard deviation: 4.564 years a. Calculate the standard error of this sample mean. b. Determine and interpret a 90% confidence interval for the mother’s mean age (at student’s birth) in the population of all students at this university. c. How would a 99% confidence interval compare to the 90%...
Students in an introductory statistics class were asked to report the age of their mothers when...
Students in an introductory statistics class were asked to report the age of their mothers when they were born. Summary statistics include Sample size: 28 students Sample mean: 29.643 years Sample standard deviation: 4.564 years a. Calculate the standard error of this sample mean. b. Determine and interpret a 90% confidence interval for the mother’s mean age (at student’s birth) in the population of all students at this university. c. How would a 99% confidence interval compare to the 90%...
Statistics 214 Section 5. Thousands of elementary school students in a region were recently given a...
Statistics 214 Section 5. Thousands of elementary school students in a region were recently given a nationwide standardized exam to test their writing skills. In a simple random sample of 280 students, 192 students passed this exam. a) Construct a 99% confidence interval for the proportion of elementary school students in the region who passed the exam. Round the endpoints of the interval to three decimal places. b) Using a complete sentence, interpret the confidence interval in the context of...
A community survey sampled 1923 people in Colorado and asked them how long it took them...
A community survey sampled 1923 people in Colorado and asked them how long it took them to commute to work each day. The sample mean one-way commute time was 25.1 minutes with a standard deviation of 13 minutes. A transportation engineer claims that the mean commute time is greater than 25 minutes. Do the data provide convincing evidence that the engineer's claim is true? Use the a = 0.10 level of significance and the critical value method with the critical...
From a random sample of 66 students in an introductory finance class that uses group-learning techniques, the mean exam...
From a random sample of 66 students in an introductory finance class that uses group-learning techniques, the mean examination score was found to be 79.79 and the sample standard deviation was 2.7. For an independent random sample of 99 students in another introductory finance class that does not use group-learning techniques, the sample mean and standard deviation of exam scores were 72.14 and 8.8 respectively. Estimate with 90% confidence the difference between the two population mean scores; do not assume...
A group of 85 students in first-year biology at Western University just wrote their second midterm....
A group of 85 students in first-year biology at Western University just wrote their second midterm. Because the first year tests involve a group component in which students learn the correct answers to the midterm questions at the end of the exam, they each know what they scored on the test. Based on their individual results, they computed a mean midterm mark of 19 (it was a test marked out of 25), with standard deviation of 4.3 marks. They considered...
4. A survey asked a random sample of 363 first-year students how many hours they studied...
4. A survey asked a random sample of 363 first-year students how many hours they studied during a particular week. The mean was 15.3 hours. Suppose we know that the population standard deviation is 8.5 hours. Construct a 90%, 95% and 99% confidence interval for the mean study time of all first year students at this university. Interpret the 90% confidence interval.
A random sample of 189 students were asked how many songs were in their digital music library and what fraction of them...
A random sample of 189 students were asked how many songs were in their digital music library and what fraction of them were legally purchased. Overall, they reported having a total of 117,738 songs, of which 21.6% were legal. The music industry would like a good estimate of the percentage of songs in students' digital libraries that are legal. a) What is the parameter being estimated? What is the population? What is the sample size? b) Construct a 99% confidence...
16.19) A class survey in a large class for first-year college students asked, "About how many...
16.19) A class survey in a large class for first-year college students asked, "About how many hours do you study in a typical week?". The mean response of the 452 students was x¯¯¯ = 13 hours. Suppose that we know that the study time follows a Normal distribution with standard deviation 7 hours in the population of all first-year students at this university. What is the 99% confidence interval (±0.001) for the population mean? Confidence interval is from to hours.
Statistics 214 Section 5. Thousands of elementary school students in a region were recently given a nationwide standardized exam to test their writing skills. In a simple random sample of 280 students, 192 students passed this exam. a) Construct a 99% confidence interval for the proportion of elementary school students in the region who passed the exam. Round the endpoints of the interval to three decimal places. b) Using a complete sentence, interpret the confidence interval in the context of...
4. A survey asked a random sample of 363 first-year students how many hours they studied during a particular week. The mean was 15.3 hours. Suppose we know that the population standard deviation is 8.5 hours. Construct a 90%, 95% and 99% confidence interval for the mean study time of all first year students at this university. Interpret the 90% confidence interval.
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