Problem 2A professor has given the same exam to every Stats class for the last 30 years (during which thousands ofstudents have taken the exam), with a historical mean of 70.8 and a standard deviation of 10.1. Moreover,the historical exam results closely follow a normal distribution. This year he experiments by using a totallynew teaching method to the class of 25 students, but he gives them the same exam as in all prior years.Part aHow likely is a randomly selected student from last year (before the new teaching method) to have scoredmore than 80? Part bRefer to Problem 2. The professor considers his new teaching method to be successful if, in his own words, "hesees more scores around the mean". What exam results are required for this to happen (with 95% certainty)?

Answered: Problem 2 A professor has given the…

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

Part 1 of 4 Victoria, an accomplished marathon runner, claims that the standard deviation for her time to run a 26.2 mile marathon is less than 17.5 minutes. To test her claim, Victoria looks up 11 of her race times (in minutes): 227.2, 233.3, 259.7, 265.8, 252.1, 228.8, 222.6, 202.9, 214.5, 237.2, 267.7 Perform a hypothesis test using a 9% level of significance to test Victoria's claim. Step 1: State the null and alternative hypotheses. 17.5 Ha:0
Both pictures go hand in hand
Suppose that El Camino is studying the average number of hours students study for classes per week. According to research from 2010 El Camino students spent an average of 21 hours a week studying for classes. El Camino wants to study if this average has changed. To do this they take a random sample of 81 current students and find that the average student spent 19.3 hours studying with a standard deviation of 6.4 hours. (Note: You may assume there are approximately 20,000 El Camino students). (a) Carry out a hypothesis test at α = .05 to test the claim that the average number of hours per week that El Camino students study has changed since 2010. (b) Describe what it would mean in this situation to make a Type I error (c) Describe what it would mean in this situation to make a Type II error (d) Construct a 95% confidence interval for the average number of hours studied by El Camino students per week. Make sure to interpret your interval.
You are interested in studying the average gestational length of pregnancies among African American women in the United States to see if it is different from the rest of the US population. The population mean for gestational length is 39 weeks with a standard deviation of 2 weeks. You take a simple random sample of 22 African American women that gave birth in the last year and find that their mean gestational length is is 38.5 weeks. If you decide to conduct a two-sided test with α = .05. What is the power of this test?
An English teacher has been teaching a sixth grade composition class for many years. He has the feeling that over the past several years, the writing ability of students has changed. A national test of proficiency in composition was administered 5 years ago. The resulting distribution of scores was normally shaped, had a mean of 85 and a standard deviation of 10.9. In order to test his feeling, he gives his present class of 43 students the same proficiency test. The resulting mean is 80 and the standard deviation is 8.7. a. What is the alternative hypothesis? b. What is the null hypothesis? c. What is your conclusion, using á = 0.052 tail? d. What type error may you be making because of your conclusion in part c?
A recent Gallup Poll interviewed a random sample of 1523 adults. Of these, 868 bought a lottery tickets in the past year. Suppose that in fact (unknown to Gallup) exactly 60% of all adults bought a lottery ticket in the past year. If Gallup took many simple random samples of 1,523 people, the sample proportion who bought a ticket would vary from sample to sample. The sampling distribution would be close to normal with a mean of 0.6 and a standard deviation of___ A)0.4899 B)0.0251 C)0.00016 D)0.0126
A study is conducted to compare the performance of students with more than one personal electronic gadget and those with only one. A number of them were taken as subjects for the study. The mean grades of these students and the standard deviations are shown below: For one gadget: The mean is 83, standard deviation is 12, and sample size is 7. For more than one gadget: The mean is 79, standard deviation is 13, and sample size is 5. Is it possible to conclude that there is no significant difference in the mean grades of the two types of students at a 95% confidence interval? Note: This is a two-tailed test. Also take note that this is finding the difference between two population means.
In a certain populalion, let us assume that IQ scores are normally distributed with mean of 100 and standard devialion of 15. What percentage of the population have IQ scares more than 116? Select one: a. 0.6808 O b. 0.2327 O c. 0.3192 C d. 0.8577 e. 0.1423 f. 0.7673
A team of researchers found that age distributions in a population of 100,000 people was not Normal. However, after they took a large number of simple random samples, each with (N=100), they observed that the sampling distribution of mean tended toward Normality. Really? Why is it possible?
Suppose a researcher pbserves a population of 12 people and computes SS=204. What is the variance? What is the standard deviation?
3 In the 1800s, German physician Carl Reinhold, took millions of axillary (i.e. armpit) temperatures from soldiers. This study established that body temperature is normally distributed and the standard normal human body temperature is 98.6℉ with a standard deviation of 0.72 ℉. In a recent study, American researchers obtained 5,000 axillary temperatures from a Los Angeles hospital. The mean of these temperature readings was 97.9 ℉. Assuming a Type I error risk of no more than 5%, did the findings support the theory that human, body temperature has decreased since the 1800s? What is the standard error? (round to nearest hundredth) What is the Z obt? (round to the nearest tenth)

Recommended textbooks for you

MATLAB: An Introduction with Applications

Statistics

ISBN:

9781119256830

Author:

Amos Gilat

Publisher:

John Wiley & Sons Inc

Probability and Statistics for Engineering and th…

Statistics

ISBN:

9781305251809

Author:

Jay L. Devore

Publisher:

Cengage Learning

Statistics for The Behavioral Sciences (MindTap C…

Statistics

ISBN:

9781305504912

Author:

Frederick J Gravetter, Larry B. Wallnau

Publisher:

Cengage Learning

MATLAB: An Introduction with Applications

Statistics

ISBN:

9781119256830

Author:

Amos Gilat

Publisher:

John Wiley & Sons Inc

Probability and Statistics for Engineering and th…

Statistics

ISBN:

9781305251809

Author:

Jay L. Devore

Publisher:

Cengage Learning

Statistics for The Behavioral Sciences (MindTap C…

Statistics

ISBN:

9781305504912

Author:

Frederick J Gravetter, Larry B. Wallnau

Publisher:

Cengage Learning

Elementary Statistics: Picturing the World (7th E…

Statistics

ISBN:

9780134683416

Author:

Ron Larson, Betsy Farber

Publisher:

PEARSON

The Basic Practice of Statistics

Statistics

ISBN:

9781319042578

Author:

David S. Moore, William I. Notz, Michael A. Fligner

Publisher:

W. H. Freeman

Introduction to the Practice of Statistics

Statistics

ISBN:

9781319013387

Author:

David S. Moore, George P. McCabe, Bruce A. Craig

Publisher:

W. H. Freeman

SEE MORE TEXTBOOKS