In Problems 19-22, determine whether or not the histogram indicatesthat a normal distribution could be used as a model for the variable 21. Length of Phone Calls The relative frequency histogramrepresents the length of phone calls on my wife's cell phoneduring the month of SeptemberLength ofPhone Calls0.400.300.200.100 2 468 10 12 14Length (in minutes)Relative Frequency

21. From the given histogram, the bars represents the relative frequencies for the lengths of the…

Answered: In Problems 19-22, determine whether or…

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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In a study investigating the effect of car speed on accident severity, 5,000 reports of fatal automobile accidents were examined, and the vehicle speed at impact was recorded for each one. For these 5,000 accidents, the average speed was 44 mph and the standard deviation was 14 mph. A histogram revealed that the vehicle speed at impact distribution was approximately normal. (Use the Empirical Rule.) (a) Approximately what percentage of these vehicle speeds were between 30 and 58 mph? approximately % (b) Approximately what percentage of these vehicle speeds exceeded 58 mph? (Round your answer to the nearest whole number.) approximately %
A webwork.bmcc.cuny.edu/ Problem 4. A pharmaceutical manufacturer is concerned about the impurity concentration in pills, and it is anxious that this concentration not exceed 3%. It is known that in any production run the impurity concentrations follow a normal distribution. A random sample of 25 pills from a production run was checked and the sample mean impurity concentration was found to be 3.35%. The sample standard deviation was 0.5. Test the null hypothesis that the population mean impurity concentration is 3% against the alternative that it is more than 3%. Use a 5% significance level. Answer the following, and round off your answer to three decimal places. (a) What is the test statistic used in the decision rule? (b) What is the critical value? (c) Can the null hypothesis be rejected at a 5% significance level? A. Reject the null hypothesis. B. Do not reject the null hypothesis. Note: You can earn partial credit on this problem. preview answers
In a study investigating the effect of car speed on accident severity, 5,000 reports of fatal automobile accidents were examined, and the vehicle speed at impact was recorded for each one. For these 5,000 accidents, the average speed was 44 mph and the standard deviation was 16 mph. A histogram revealed that the vehicle speed at impact distribution was approximately normal. (Use the Empirical Rule.) (a) Approximately what percentage of these vehicle speeds were between 28 and 60 mph? approximately % (b) Approximately what percentage of these vehicle speeds exceeded 60 mph? (Round your answer to the nearest whole number.) approximately %
An article in the San Jose Mercury News stated that students in the California state university system take 4.5 years, on average, to finish their undergraduate degrees. Suppose you believe that the mean time is longer. You conduct a survey of 42 students and obtain a sample mean of 5.1 with a sample standard deviation of 1.2. Do the data support your claim at the 1% level?Note: If you are using a Student's t-distribution for the problem, you may assume that the underlying population is normally distributed. (In general, you must first prove that assumption, though.)
According to the Center for Disease Control and Prevention (CDC), the mean life expectancy in 2015 for non‑Hispanic black females was 78.1 years. Assume that the standard deviation was 15 years, as suggested by the Bureau of Economic Research. The distribution of age at death, ?, is not normal because it is skewed to the left. Nevertheless, the distribution of the mean, x¯, in all possible samples of size ?n is approximately normal if ? is large enough, by the central limit theorem. Let x¯ be the mean life expectancy in a sample of 100 non‑Hispanic black females. Determine the interval centered at the population mean ? such that 95% of sample means x¯ will fall in the interval. Give your answers precise to one decimal What are the upper and lower limits?
In this problem, assume that the distribution of differences is approximately normal. Note: For degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value by a small amount and therefore produce a slightly more "conservative" answer. In the following data pairs, A represents the cost of living index for utilities and B represents the cost of living index for transportation. The data are paired by metropolitan areas in the United States. A random sample of 46 metropolitan areas gave the following information.
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The scores on a standardized mathematics test for 8th-grade children in New York State form a normal distribution with a mean of m= 70 and a SD=10. a. What proportion of the students in the state have scores less than X=75? b. If samples of n=4 are selected from the population, what proportion of the samples will have means less than M=75? c. If samples of n=25 are selected from the population, what proportion of the samples will have means less than M=75?
In a study investigating the effect of car speed on accident severity, 5,000 reports of fatal automobile accidents were examined, and the vehicle speed at impact was recorded for each one. For these 5,000 accidents, the average speed was 44 mph and the standard deviation was 17 mph. A histogram revealed that the vehicle speed at impact distribution was approximately normal. (Use the Empirical Rule.) (a) Approximately what percentage of these vehicle speeds were between 27 and 61 mph? approximately % (b) Approximately what percentage of these vehicle speeds exceeded 61 mph? (Round your answer to the nearest whole number.) approximately %
A researcher was interested in comparing the mean grade-point-average (GPA) of students at the University of Toronto Scarborough and Mississauga campuses. Independent random samples of 8 students from the Scarborough campus and 13 students from the Mississauga campus yielded the following GPAs. You can assume the data in each group follow a normal distribution. Do the data provide sufficient evidence to conclude that the mean GPA of students at the Scarborough campus different from the mean GPA of students at the Mississauga campus? A. What statistical test is most appropriate to answer this question? B. Identify the relevant assumptions and conditions. State how these have or have not been met. C. Write an appropriate null and alternative hypothesis for this question.
1. For a normal distribution, find the percent of scores that lie between the scores having z values of z = -4 and z = 6
In a study investigating the effect of car speed on accident severity, 5,000 reports of fatal automobile accidents were examined, and the vehicle speed at impact was recorded for each one. For these 5,000 accidents, the average speed was 42 mph and the standard deviation was 12 mph. A histogram revealed that the vehicle speed at impact distribution was approximately normal. (Use the Empirical Rule.) (a) Approximately what percentage of vehicle speeds were between 30 and 54 mph? approximately % (b) Approximately what percentage of vehicle speeds exceeded 54 mph? (Round your answer to the nearest whole number.) approximately %

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