The director of the IRS has been flooded with complaints that people must wait more than 55 minutes before seeing an IRS representative. To determine the validity ofthese complaints, the IRS randomly selects 400 people entering IRS offices across the country and records the times which they must wait before seeing an IRSrepresentative. The average waiting time for the sample is 57 minutes with a standard deviation of 3 minutes. Is there overwhelming evidence to support the claim thatthe wait time to see an IRS representative is more than 55 minutes at a 0.005 significance level?Step 1 of 3: Find the value of the test statistic. Round your answer to three decimal places, if necessary.AnswerTablesKeypadKeyboard Shortcuts

The objective of this question is to determine if there is overwhelming evidence to support the…

Answered: The director of the IRS has been…

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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The honors program at Brad's university only accepts students with an entrance exam score over 400. What percentage of students would be eligible if the students at Brad's school have an average exam score of 250, with a standard deviation of 80?
Salma recently switched her primary doctor to one specializing in caring for elderly patients. On her new doctor's website, it says that the mean systolic blood pressure among elderly females is 115 millimeters of mercury (mmHg). Salma believes the value is actually higher. She bases her belief on a recently reported study of 21 randomly selected, elderly females. The sample mean systolic blood pressure was 118 mmH, and the sample standard deviation was 21 mmHg. Assume that the systolic blood pressures of elderly females are approximately normally distributed. Based on the study, at the 0.10 level of significance, can it be concluded that y, the population mean systolic blood pressure among elderly females, is greater than 115 mmHg? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.)
About 11% of men are excluded by NASA’s Astronaut Selection Program based solely on height (11% of men are less than 157.5cm or more than 190.5cm). These height requirements are not adjusted according to sex, so females are subject to the same height requirements. What percentage of females does the Astronaut Selection Program exclude, if the mean height of females is 162.6 cm with a population standard deviation of 9.7 cm?
In the 2000 census, the so-called 'short form' contained only 7 questions, including name, gender, age, race, how the person is related to the head of household, whether they are Hispanic, and whether they own or rent their home. According to U.S. Census Bureau, the average time to complete the short form is 10 minutes. Assuming a standard deviation of 2 minutes and a simple random sample of 30 persons who completed the short form, does it seem very likely that the members of such a sample would have required an average of 8 minutes or less to
A researcher wants to determine the average height of students in a university using convenience sampling. They measure the height of 15 students selected based on their availability and accessibility. The mean height of these students is 170 cm with a standard deviation of 5 cm. Can the researcher use this sample to make inferences about the population of all students at the university?
The administrator at your local hospital states that on weekends the average wait time for emergency room visits is 10 minutes. Based on discussions you have had with friends who have complained on how long they waited to be seen in the ER over a weekend, you dispute the administrator’s claim. You decide to test your hypothesis. Over the course of a few weekends, you record the wait time for 40 randomly selected patients. The average wait time for these 40 patients is 11 minutes with a standard deviation of 3 minutes. Do you have enough evidence to support your hypothesis that the average ER wait time is different than 10 minutes? You opt to conduct the test at an α = 0.025 level of significance.
Londell, an accomplished marathon runner, claims that the standard deviation for his time to run a 26.2 mile marathon is less than 11.1 minutes. To test his claim, Londell looks up 17 of his race times (in minutes): 238.6, 240, 231.4, 241.4, 251.9, 230.4, 232.1, 235.7, 234.6, 242.9, 240.5, 237.6, 242.2, 245.7, 235.7, 240.2, 233.9 Perform a hypothesis test using a 1% level of significance to test Londell's claim. Step 1: State the null and alternative hypotheses. Ho:o Ha:o (So we will be performing a left-tailed 11.1 11.1 Part 2 of 4 Step 2: Assuming the null hypothesis is true, determine the features of the distribution of test statistics. Because we are testing the population standard deviation, we will use a x² distribution with 16 ✓degrees of freedom. P(x² ? ✓✓test.) Step 3: Find the p-value of the test statistic. Sample Mean: = Sample Standard Deviation: s = p-value = Submit Part Part 3 of 4
Based on the information from the U.S census bureau the mean travel time to work in minutes for all workers 16 years old and older was 27.5 minutes. A large company with offices in several states randomly sample 85 of its workers to ascertain their commuting times. The sample mean was 23.6 minutes,and the population standard deviation is 5.41 minutes. At the 0.05 level of signifance can it be concluded that the mean commuting time is less for this particular company
There are two samples. One is a group of 8 athletes who practice and the other is a group of 5 athletes who do not practice. The mean for group 1 is 92.4 and the standard deviation is 5.83. For group 2, the mean is 81.3 and the standard deviation 7.85. the coach thinks the true mean for the athletes who did not practice is more that 8 points smaller than those who did practice. a) make the null and alternative hypotheses. calculate the test statistic and give an explanation as to why you chose this test statistic.
Assume a media agency reports that it takes television streaming service subscribers in the U.S. an average of 6.60 days to watch the entire first season of a television series, with a standard deviation of 4.21 days. Scarlett is an analyst for an online television and movie streaming service company that targets to the 18-50 age bracket. She wants to determine if her company's customers exhibit shorter viewing rates for their series offerings. Scarlett plans to conduct a one-sample ?-z-test, with significance level of ?=0.05α=0.05, to test the null hypothesis, ?0:?=6.60 daysH0:μ=6.60 days, against the alternative hypothesis, ?1:?<6.60 days.H1:μ<6.60 days. The variable ?μ is the mean amount of time, in days, that it takes for customers to watch the first season of a television series. Scarlett selects a simple random sample of 740 customers who watched the first season of a television series from the company database of over 25,000 customers that qualified. She compiles the…
A college admissions officer believes that students enrolling from Shawnee school District have higher SAT scores than those who enroll from West River School District. A sample of 30 students from each district is selected. The average SAT score for the group from the Shawnee district is 656 with a standard deviation of 100. The average SAT score for the group from the West River district is 560 with a standard deviation of 90. Is the belief of the admissions officer substantiated?
We have the number of recorded children from 20 randomly selected barangays in the Philippines to help us estimate the number of Filipino children aged 12- 23 months who did not receive any vaccinations appropriate for their age. 16, 22, 26, 31, 45, 18, 24, 26, 34, 46, 19, 24, 27, 35, 55, 19, 25, 28, 37, 58 A. Can we compute for the population standard deviation? B. If yes, what is the population standard deviation? Use the computational formula. If no, why not? C. Can we compute for the sample standard deviation? D. If yes, what is the sample standard deviation? Use the computational formula. If no, why not?

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