An article gave the following summary information for fracture strengths (MPa) of n = 169 ceramic bars fired in a particular kiln: x = 72.32, s = 3.77.(a) Calculate a (two-sided) confidence interval for true average fracture strength using a confidence level of 95%. (Round your answers to two decimal places.)MPaDoes it appear that true average fracture strength has been precisely estimated?Yes, this is a very narrow interval.O No, this is a very wide interval.(b) Suppose the investigators had believed a priori that the population standard deviation was about 3 MPa. Based on this supposition, how large a sample would have been required to estimate to within 0.5 MPa with 95% confidence?ceramic bars

From the provided information, Sample size (n) = 169 Sample mean (x̄) = 72.32 Sample standard…

Answered: An article gave the following summary…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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B. The test statistic, t, =____ C. The P-value is ____ D. State the conclusion for the test. Reject H0. or Fail to reject H0. E. Construct a confidence interval suitable for testing the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests. ___<μ1−μ2<___ F. Does the confidence interval support the conclusion of the test? (Yes/ No) because the confidence interval contains (zero/ only positive value/ only negative values).
Here are summary statistics for randomly selected weights of newborn girls: n= 36, x = 3211.1 g, s= 689.4 g. Use a confidence level of 99% to complete parts (a) through (d) below. a. Identify the critical value t2 used for finding the margin of error. /2 re (Round to two decimal places as needed.) b. Find the margin of error. =ヨ (Round to one decimal place as needed.) C. Find the confidence interval estimate of u. (Round to one decimal place as needed.) d. Write a brief statement that interprets the confidence interval. Choose the correct answer below. OA. One has 99% confidence that the sample mean weight of newborn girls is equal to the population mean weight of newborn girls. OB. One has 99% confidence that the interval from the lower bound to the upper bound contains the true value of the population mean weight of newborn girls. OC. Approximately 99% of sample mean weights of newborn girls will fall between the lower bound and the upper bound. O D. There is a 99% chance that the…
A random sample of n = 16 mid-sized cars tested for fuel consumption gave a mean of x = 20.01 miles per gallon with a standard deviation of s = 2.84 miles per gallon. Assuming that the miles per gallon given by all mid-sized cars have a normal distribution, find a 99% confidence interval for the population mean, H. Round your answers to two decimal places. i i
You want to obtain a sample to estimate how much parents spend on their kid's birthday parties. Based on the previous study, you believe the population standard deviation is approximately σ=63.1σ=63.1 dollars. You would like to be 90% confident that your estimate is within 2.5 dollar(s) of average spending on birthday parties. How many parents do you have to sample?
A 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 school
es A sample of 12 fossil skeletons of an extinct species of bird has been collected. The mean length of the skulls in this sample is 5.29 cm and the standard deviation of the sample is 0.21 cm. Assuming that such measurements are normally distributed, find a 90% confidence interval for the population mean length of the skulls of this species of bird. You may want to use one of these: qt (p-0.10, df-11, lower. tail-FALSE)=1.36343 qt(p-0.05, df-11, lower.tail-FALSE) =1.795885 qnorm(0.10, mean-0, sd-1, lower.tail-FALSE)=1.281552 qnorm(0.05, mean-0, sd-1, lower.tail=FALSE)=1.644854 O (4.945, 5.635) O (4.913, 5.667) O (5.021, 5.559) O (5.181, 5.399)
As a bonus assignment a former student checked if your professor gave a statisticallysignificant difference in grades between his male and female students. She based herstudy based on grades assigned in intermediate Econ courses (Econ 303, 305 and 317)and her sample included nm = 485 male students and nf = 264 female students. Theaverage grades received were xm = 84.6 and xf = 85.8 The population standad deviation were σ m = 12.0 and σ f = 11.4 8. From the same extra-credit study as in question 7 see above, this former student found that the proportion of female students in principle courses (Econ 203, 205) was ?̅? = 0.380, while the proportion of female students in intermediate courses (Econ 303, 305, 317) was ?̅? = 0.352. The principle courses sample size was np = 782, while the intermediate courses sample size was ni = 749. Test the hypothesis that female students are less in intermediate courses using a 90% confidence level and the p-value approach.
Here are summary statistics for randomly selected weights of newborn girls: n=36, x=3150.0 g, s=695.5 g. Use a confidence level of 99% to complete parts (a) through (d) below.
A random sample of students taking STAT 201 this semester was pulled. Among other things, the survey asked the number of hours the student spent studying for the final exam. StatCrunch was used to create the output for a 95% confidence interval estimate for the population mean number of hours students spend studying for the final exam. 95% confidence interval results: Variable Sample Mean Std. Err. DF L. Limit U. Limit # hours 6.05 0.31 64 5.42 6.67 Give the value of the point estimate used to calculate the confidence interval. (Do not round your answer)

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