Multiple choiceTina's science fair project was to estimate the mean amount of chemicals in her city's watersupply. At first, she had decided to use a random sample of 15 observations. But her teacher askedher to take 35 observations. The mean and standard deviation from 35 observations turned out tobe approximately the same as those from 15 observations. Is there any advantage in using 35observations instead of 15 observations?There is no advantage. Because the mean and the standard deviation are about thesame, the confidence interval computed using 35 observations should beapproximately the same as that computed using 15 observations.There is no advantage. In fact, the 20 extra observations will increase the likelihood oferror.There is no advantage. Because she took 35 observations instead of 15 observations,the confidence interval using 35 observations will be wider than that using 15observations.There is some advantage. Because she took 35 observations instead of 15observations, the confidence interval using 35 observations will be narrower than thatusing 15 observations.There is some advantage. With 35 observations, she will be able to compute an exactz-confidence interval instead of an approximate t-confidence interval.

Solution: Relationship between the sample size and the confidence interval: If the sample size or…

Answered: Tina's science fair project was to…

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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Logan and Brian began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. Logan took a test in Art History and earned a 76.8, and Brian took a test in English and earned a 68.9. Use the fact that all the students' test grades in the Art History class had a mean of 71.9 and a standard deviation of 11.6, and all the students' test grades in English had a mean of 61 and a standard deviation of 9.4 to answer the following questions.a) Calculate the z-score for Logan's test grade.z=z= [Round your answer to two decimal places.] b) Calculate the z-score for Brian's test grade.z=z= [Round your answer to two decimal places.]c) Which person did relatively better? Logan Brian They did equally well.
Alice was told that her reading test score was one standard deviation below to me if test scores were approximately normal with m= 86 and standard deviation= 4. What was Alice's score?
Suppose the scores on your last Algebra 2 test were normally distributed, with a mean of 81% and a standard deviation of 3%. To show you how you compared to your classmates, the teacher did not record your grades as per- centages, instead, she wrote them as z-scores. You look at your paper and see "2.66" written at the top. What was your score as a percentage? Explain how you determined your answer.
For an exam with a mean of = 74 and a standard deviation of s = 8, Mary has a score of X = 80, Bob’s score corresponds to z = +1.50, and Sue’s score is located above the mean by 10 points. List the students in order from the smallest score to the largest score. Show your computation and draw a picture and place their values.
The average of the final exam grades of a course attended by four hundred students is calculated as 60 points and the standard deviation as 15 points. A letter grade will be given to those who score 80 and above in the exam. What is the rate of 0 and above and how many people can be estimated to get A?
Dakota and Bill began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. Dakota took a test in Science and earned a 79.9, and Bill took a test in Math and earned a 63.5. Use the fact that all the students' test grades in the Science class had a mean of 73.5 and a standard deviation of 11.4, and all the students' test grades in Math had a mean of 67 and a standard deviation of 8.3 to answer the following questions. a) Calculate the z-score for Dakota's test grade. [Round your answer to two decimal places.] b) Calculate the z-score for Bill's test grade. [Round your answer to two decimal places.] c) Which person did relatively better? O Dakota O Bill O They did equally well. Submit Question 3
In class A, Jamir got 85 for his first test. Jamir's class mean was 75 and the standard deviation was 5.In class B, Laurabelle got 80 in her first test. Laurabelle's class mean was 50 and the standard deviation was 10.In a fair comparison of the two students in two different classes, who did better in his or her test. (Compare Jamir and Laurabelle's standing in their classes.Note Z-score gives that information.) Jamir Laurabelle Both did the same none of the above
Rebecca and Emma began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. Rebecca took a test in English and earned a 71, and Emma took a test in Social Studies and earned a 70.4. Use the fact that all the students' test grades in the English class had a mean of 71.5 and a standard deviation of 10.7, and all the students' test grades in Social Studies had a mean of 64.1 and a standard deviation of 9.5 to answer the following questions. a) Calculate the z-score for Rebecca's test grade. b) Calculate the z-score for Emma's test grade. = Z c) Which person did relatively better? Rebecca O Emma O They did equally well.
Suppose that the mean and standard deviation for vertical jump scores are 40 and 6 cm respectively. A York student jumps 52 cm on the vertical score. Translate the student’s jump into a z-score.
Two friends, Karen and Jodi, work different shifts for the same ambulance service. They wonder if the different shifts average different numbers of calls. Looking at past records, Karen determines from a random sample of 40 shifts that she had a mean of 5.1 calls per shift. She knows that the population standard deviation for her shift is 1.2 calls. Jodi calculates from a random sample of 31 shifts that her mean was 5.8 calls per shift. She knows that the population standard deviation for her shift is 1.4 calls. Test the claim that there is a difference between the mean numbers of calls for the two shifts at the 0.01 level of significance. Let Karen's shifts be Population 1 and let Jodi's shifts be Population 2. Step 3 of 3 : Draw a conclusion and interpret the decision.

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