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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Similar questions

On a Physicians Licensure Exam with a population mean of 83 and standard deviation of 8. Jenny scores 4 points below the mean, Jeffrey had a score of x-84 and Jolly had a z-score of 0.30. Place these three students in order from the lowest to highest.
April and Heather began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. April took a test in Science and earned a 74.4, and Heather took a test in English and earned a 69.7. Use the fact that all the students' test grades in the Science class had a mean of 71.3 and a standard deviation of 8.9, and all the students' test grades in English had a mean of 60.5 and a standard deviation of 8.5 to answer the following questions. a) Calculate the z-score for April's test grade. b) Calculate the z-score for Heather's test grade. c) Which person did relatively better? April Heather O They did equally well. Submit Question logi $22 *3 F4 F8 7. 8. %4
You are comparing data from two similar experiments that have a mean of 53. Experiment A has a standard deviation of 3.4 and experiment B has a standard deviation of 1.5. What does this tell you about the data in the experiments?
The systolic blood pressure of adults in the USA is nearly normally distributed with a mean of 117 and standard deviation of 15 .Someone qualifies as having Stage 2 high blood pressure if their systolic blood pressure is 160 or higher. d. What two values divide this normal curve into a middle 97%, in other words, what two values represent the middle 97% of blood pressures?  Put the lower number FIRST! and  mmHg e. How many standard deviations away would a blood pressure of 140 be?     f. Would this be considered unusual? Not Unusual Very Unusual Somewhat Unusual
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 39 shifts that she had a mean of 4.7 calls per shift. She knows that the population standard deviation for her shift is 1.5 calls. Jodi calculates from a random sample of 31 shifts that her mean was 5.4 calls per shift. She knows that the population standard deviation for her shift is 1.2 calls. Test the claim that there is a difference between the mean numbers of calls for the two shifts at the 0.02 level of significance. Let Karen's shifts be Population 1 and let Jodi's shifts be Population 2. Step 2 of 3 :   Compute the value of the test statistic. Round your answer to two decimal places.
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 38 shifts that she had a mean of 4.6 calls per shift. She knows that the population standard deviation for her shift is 1.1 calls. Jodi calculates from a random sample of 31 shifts that her mean was 5.3 calls per shift. She knows that the population standard deviation for her shift is 1.5 calls. Test the claim that there is a difference between the mean numbers of calls for the two shifts at the 0.02 level of significance. Let Karen's shifts be Population 1 and let Jodi's shifts be Population 2. Step 2 of 3 :   Compute the value of the test statistic. Round your answer to two decimal places.
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 32 shifts that she had a mean of 4.8 calls per shift. She knows that the population standard deviation for her shift is 1.4 calls. Jodi calculates from a random sample of 40 shifts that her mean was 4.2 calls per shift. She knows that the population standard deviation for her shift is 1.1 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 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places.
Suppose that Jett achieves a score of 1250 on the SAT, and his sister Kate scores 29 on the ACT. The SAT scores are normally distributed with a mean of 1100 and standard deviation of 250. The ACT scores are normally distributed with a mean of about 20 and standard deviation of 5. Who did better, relative to their peers?
If the mean of the data is 130 with a standard deviation of 10, what percent of the data falls between the values of 100 and 160?
For her test grades, Gena has a mean = 65 and standard deviation = 25. Patti has a mean = 65 and standard deviation = 5. For which of the students can you more accurately predict the next test score, and why? Consider the variability of scores. Who is more likely to do either extremely well or extremely poorly on the next exam, and why? Explain the reason for adjusting the formula of the standard deviation/variance with n - 1 in the denominator?
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.

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