1. An automobile manufacturer timed a random sample of 10 mechanics in the performance of a particular maintenance task. If it took them on average 24.05 minutes with a standard deviation of 2.68 minutes, construct and interpret a 95%-confidence interval for the population variance arrived at using the x² (n-1)s² distribution of the quantity (the customary method.)

1. An automobile manufacturer timed a random sample of 10 mechanics in the performance of a particular maintenance task. If it took them on average 24.05 minutes with a standard deviation of 2.68 minutes, construct and interpret a 95%-confidence interval for the population variance arrived at using the x² (n-1)s² distribution of the quantity (the customary method.)

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Researchers conducted a study to determine whether magnets are effective in treating back pain. The results are shown in the table for the treatment (with magnets) group and the sham(or placebo) group. The results are a measure of reduction in back pain. Assume that the two samples are independent simple random samples selected from normally distributedpopulations, and do not assume that the population standard deviations are equal. Complete parts (a) and (b) below. Use a 0.05significance level for both parts. a. Test the claim that the two samples are from populations with the same mean. What are the null and alternative hypotheses? What is the test statistic, t? What is the P-value? State the conclusion for the test. b. Construct a confidence interval suitable for testing the claim that the two samples are from populations with the same mean.
1. The heights ( in inches) of the students on a campus are assumed to have a normal distribution with a standard deviation of 4 inches. A random sample of 49 students was taken with M=68 inches. The 95% confidence interval for the population mean is:
1. A simple random sample of 21 people with early-onset dementia have the mean age at diagnosis of 52.3 years and the standard deviation of 6.5 years. Assume that ages at the diagnosis of dementia are normally distributed. We are to perform a hypotheses test to determine whether mean age at diagnosis of all people with early-onset dementia is different from 55 years. a. If one percent significance level is used then: i. RR = {t ≥ 2.528} ii. RR = {t ≤ −2.528} iii. RR={t≤−2.528}∪{t≥2.528} iv. RR = {t ≤ −2.845} v. RR = {t ≥ 2.845} vi. RR = {t ≤ −2.845}∪{t ≥ 2.845} b. At one percent significance level, we can conclude that mean age at diagnosis of all people with early-onset dementia is i. Is equal to 55 years 2. Is equal to 52.3 years 3. Is not equal to 52.3 years 4. Is not equal to 55 years
Grand Sun Buffet is a large restaurant chain. After paying for a meal at Grand Sun Buffet, customers are asked to rate the quality of the food as a 1, 2, 3, 4, or 5, where a rating of 1 means "not good" and 5 means "excellent". The customers' ratings have a population mean of µ=3.88, with a standard deviation of o=1.38. Suppose that we will take a random sample of n=8 customers' ratings. Let x representřthe sample mean of the 8 customers' ratings. Consider the sampling distribution of the sample mean x. Complete the following. Do not round any intermediate computations. Write your answers with two decimal places, rounding if needed. (a) Find u- (the mean of the sampling distribution of the sample mean). (b) Find o– (the standard deviation of the sampling distribution of the sample mean). Continue Submit Assignment O 2022 McGraw Hill LLC. All Rights Reserved. Terms of Use | Privacy Center | Accessibility tv ?? 23 DII F3 F6 F7 F8 3 24 % & 3 4 6 7 81 2'
2. The travel time to their workplace of a random sample of workers from the central zone of the country is observed in the following frequency table: Minutes 15 - 27 27 39 39 51 51 63 63 75 Frequency 5 15 20 15 10 It is assumed that the travel times approximate a normal distribution. Calculate: a) A 90% confidence interval for the population average of travel times. b) A 90% confidence interval for the population standard deviation.
The average dues paid by students at state universities across the country were $2236 per student last year. The average for a random sample of 500 students this year is $2350. Given the following hypotheses, Ho: 4 = 2236 (The average fees are the same as last year.) Ha: M + 2236 (The average fees are not the same as last year.) compute the p-value for the sample result. Assume the population standard deviation is $724. If the significance level is 5%, can the null hypothesis be rejected?
C.26. A clinic took temperature readings of 250 flu patients over a weekend and discovered the temperature distribution to be Gaussian, with a mean of 101.40°F and a standard deviation of 0.5610°F. a) What is the fraction of patients expected to have a fever greater than 102.97°F ? b) What fraction of patients is expected to have a temperature between 101.06°F and 102.24°F?
A random sample of 40 college students has a mean earnings of $3120 with a standard deviation of $677 over the summer months. Determine whether a normal distribution or a t-distribution should be used or whether neither of these can be used to construct a confidence interval. Question 2 options: Cannot use normal distribution or t-distribution. Use normal distribution. Use the t-distribution.
2. The average gasoline price of one of the major oil companies has been $1.00 per gallon. Because of shortages in production of crude oil, it is believed that there has been a significant increase in the average price. In order to test this belief, we randomly selected a sample of 36 of the company's gas stations and determined that the average price for the stations in the sample was $1.04. Assume that the standard deviation of the population (o) is $0.12. a) State the null and the alternative hypotheses for testing the belief. b) Describe a Type I error and a Type II error for this situation. c) What is the critical value at a = .05? d) what's your What is the t-statistic or z-statistic associated with the above sample results?
(a) Calculate n . s for these data, the mean of the variances of the four samples and the value of F.(b) Assuming that these data constitute random samples from four normal populations with the same standard deviation, test atthe 0.01 level of significance whether the differences among the four sample means can be attributed to chance.
1. In a random sample of fishes from a pond, the mean tail length was 6.0 mm and the reference tail length for the species was found to be 4.0 mm with a standard deviation of 2.0. if there are 16 fishes, what would be the z score and which hypothesis would be accepted? 2. If the mean for group 1 in a clinical trial for the time for a drug X to act is 10 minutes and 8 minutes for group 2 and if the standard deviation for group 1 is 1.0 and group 2 is 2.0. If there are 4 persons in both groups, what is the t value and which hypothesis would you accept if t critical is 3.14 ( 2 sided) 3. A geneticist is examining the relationship between genotype and phenotype for roses. He calculated a chi-square value of 4.1 for a 2 x 2 table. If the scenario is two sided, which hypothesis did he accept? 4.
A random sample of 16 statistics examinations from a large population was taken. The average score in the sample was 78.6 with a sample variance of 64. We are interested in determining whether the average grade of the population is significantly more than 75. Assume the distribution of the population of grades is normal. The value of the test statistic is 1.80 O b. 3.6 С. 0.45 2.