![MATLAB: An Introduction with Applications](https://www.bartleby.com/isbn_cover_images/9781119256830/9781119256830_smallCoverImage.gif)
Concept explainers
1. Someone reported a confidence interval of (1032.64, 1037.36). Given that the
2. A certain motor is designed to spin at 3600 rpm. However, due to differences in the manufacturing process, some are faster and some are slower.
Engineers testing 20 of such motors find that the standard deviation of the rpm of the 20 tested motors is 45 rpm. Use this information to calculate the margin of error, at the 90% confidence level. Round to 1 decimal place.
3. Engineers measure the melting point under carfully controlled conditions to find the estimate of the true mean melting point of a metal. The true standard deviation of all melting points for this metal is 3.2 degrees C. How many measurements will be needed to obtain a margin of error of 0.8 degrees C with 95% confidence? Round answer up to whole number.
![Check Mark](/static/check-mark.png)
From the provided information,
Sample size (n) = 32
Confidence interval is (1032.64, 1037.36)
Standard deviation (σ) = 6.8
The required confidence level can be obtained as:
Step by stepSolved in 3 steps with 1 images
![Blurred answer](/static/blurred-answer.jpg)
- A random sample of 88 observations produced a mean x=25.8 and a standard deviation s=2.5. a. Find a 95% confidence interval for μ. b. Find a 90% confidence interval for μ. c. Find a 99% confidence interval for μ. a. The 95% confidence interval is (enter your response here,enter your response here).arrow_forwardSee pictures for question D and E and (A, B and Cand was submitted on a different question. According to a report done by S & J Power, the mean lifetime of the light bulbs it manufactures is 44 months. A researcher for a consumer advocate group tests this by selecting 16 bulbs at random. For the bulbs in the sample, the mean lifetime is 47 months. It is known that the population standard deviation of the lifetimes is 5 months. Assume that the population is normally distributed. Can we conclude, at the 0.10 level of significance, that the population mean lifetime, μ, of light bulbs made by this manufacturer differs from 44 months? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below.arrow_forwardA statistics class is estimating the mean height of all female students at their college. They collect a random sample of 42 female students and measure their heights. The mean of the sample is 65.3 inches and the sample standard deviation is 5.4 inches. Find the 90% confidence interval for the mean height of all female students in their school? Assume that the distribution of individual female heights at this school is approximately normal. 1. The t value is 1.3025 2. The standard error has a value of -- 3. The margin of error has a value of 4. Find the 90% confidence interval for the mean height of all female students in their schoolarrow_forward
- (Continuing from the last question, with the same values) A researcher is interested in testing whether college students send more or fewer texts per day, relative to the general population. The researcher finds out that the population average of texts sent per day is µ = 112, but is unable to find out the population standard deviation. This researcher then recruits 25 college students, and asks about their texting. They report a sample mean of M = 120, with a SS= 1200 In the last question, you computed the estimated standard error (sM) For this question, compute the value of the t-test. t =?arrow_forwardA sample of n = 8 scores has a mean of M = 16. For this sample, ΣX = 128. Is this true or false?arrow_forwardYou measure 40 randomly selected textbooks' weights, and find they have a mean weight of 78 ounces. Assume the population standard deviation is 6.4 ounces. Based on this, construct a 90% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places εμεarrow_forward
- tion. Use this information to construct the 90% and 95% confidence intervals fc of the confidence intervals. ce of a certain stock was $123.13. Assume the population standard deviation isarrow_forwardPlease help with 6 a-barrow_forwardThe random sample of n=75�=75 yielded a sample mean of x¯=26�¯=26.Assume that we know the population standard deviation is σ=30�=30. Step 2 of 3 : Calculate a 95% confidence interval for the population mean. Round your answers to 2 decimals places.arrow_forward
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman
![Text book image](https://www.bartleby.com/isbn_cover_images/9781119256830/9781119256830_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305251809/9781305251809_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305504912/9781305504912_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9780134683416/9780134683416_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781319042578/9781319042578_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781319013387/9781319013387_smallCoverImage.gif)