4.52On a particular test for a very large statistics class, a random sample of n = 4 students has a mean gradeX = 75 and s = 8. The grades for the entire class are known to be normally distributed. For the unknownpopulation mean of the grades, find (a) the 95% confidence interval and (b) the 99% confidence interval.Ans. (a) Approximately from 62 to 88 (b) Approximately from 52 to 98

Given that Sample size n =4 Sample mean=75 Sample standard deviation =8

Answered: 4.52 On a particular test for a very…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Question 81 parts D and E
Question 5 Assume that we want to construct a confidence interval. Do one of the following, as appropriate: Find the critical value ta/2 Find the critical value za/2 State that neither the normal distribution nor the t distribution applies. The confidence level is 99%, ơ is not known, and the histogram of 59 player salaries (in thousands of dollars) of football players on a team is as shown. 30- 400 12000 1600 20000 Salry housands of dollam) O A. ta/2 = 1.67 O B. Neither the normal distribution nor the t distribution applies. OC. ta/2 = 2.00 O D. Za/2 = 2.66
Question 9: compute a 95% confidence interval for the average blood pressure range of any individual that will take the blood pressure medication.
Completed 0 of 4 Questions ( 1 4 > O Save V Finish 2 3 Yoonie is a personnel manager in a large corporation. Each month she must review 25 of the employees. From past experience, she has found that the reviews take her approximately 2 hours each to do with a population standard deviation of 1.2 hours. Let X be the random variable representing the time it takes her to complete one review. Assume X is normally distributed. Let X be the random variable representing the mean time to complete the 25 reviews. Assume that the 25 reviews represent a random set of reviews. a. X is normally distributed with a mean of and a standard deviation of 2 1.2 and a standard error of the mean Round your answer to 2 decimal places. b. X is normally distributed with a mean of Enter a number Enter a number Submit (2 attempts remaining) Us O 9I 11
Question 5, 8.3.49
1.
Question 12 Astudent was asked to find a 90% confidence interval for the proportion of students who take notes using data from a random sample of size n = 86. Which of the following is a correct interpretation of the interval 0.13 p < 0.27? Check all that are correct. With 90% confidence, the proportion of all students who take notes is between 0.13 and0.27. U There is a 90% chance that the proportion of the population is between 0.13 and 0.27. O There is a 90% chance that the proportion of notetakers in a sample of 86 students wilL be between 0.13 and 0.27. O The proprtion of all students who take notes is between 0.13 and 0.27, 90% of the time. OWith 90% confidence, a randomly selected student takes notes in a proportion of their classes that is between 0.13 and 0.27.
Question 4 Suppose a random sample of size n- 100 has been selected and the sample mean in found to be x 67. The population standard deviation is assumed to be a 12. What is the 95% confidence interval estimate of u? O 164.658. 69 2521 O163 648 70.352) O 164.648, 69.352I C (64.748, 69 452)
Question 4(a) A sample of test scores is obtained. The scores are displayed as follows:11, 16, 19, 15, 7, 8, 10Test the hypothesis that the mean score is 15 at 1% significance level (b) A chemical manufacturer is concerned about the degree of contamination in the raw materialshipments purchased from a supplier. Taking a random sample of 20 shipments of raw materials,the standard deviation of contamination is 3.59. Construct the 95% confidence interval forpopulation variance
QUESTION 7 Your statistics instructor wants you to determine a confidence interval estimate for the mean test score. Past experience indicated that tests scores are normally distributed with a sample mean of 160 and a population standard deviation of 45. The critical value to estimate a 95% confidence interval of the population means is A. 1.645 B. 1.96 OC. 2.021 D. 1.684
ch.8 confidence interval mean A researcher is interested in finding a 98% confidence interval for the mean number minutes students are concentrating on their professor during a one hour statistics lecture. The study included 144 students who averaged 37.5 minutes concentrating on their professor during the hour lecture. The standard deviation was 11.3 minutes. b. With 98% confidence the population mean minutes of concentration is between (round to 3 decimal places) _____ and _____ minutes. c. If many groups of 144 randomly selected members are studied, then a different confidence interval would be produced from each group. About _____ percent of these confidence intervals will contain the true population mean minutes of concentration and about _______ percent will not contain the true population mean minutes of concentration.

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