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A manufacturer claims that the calling range (in feet) of its 900-MHz cordless telephone is greater than that of its leading competitor. A sample of 1010 phones from the manufacturer had a mean range of 11801180 feet with a standard deviation of 4141 feet. A sample of 2020 similar phones from its competitor had a mean range of 11101110 feet with a standard deviation of 3535 feet. Do the results support the manufacturer's claim? Let μ1�1 be the true mean range of the manufacturer's cordless telephone and μ2�2 be the true mean range of the competitor's cordless telephone. Use a significance level of α=0.01�=0.01 for the test. Assume that the population variances are equal and that the two populations are normally distributed. Step 2 of 4 :   Compute the value of the t test statistic. Round your answer to three decimal places.

Please no written by hand and no emage

2) You work for the FTC. A manufacturer of detergent claims that the mean weight of detergent is at least 6.5 lb. You take a random sample of 64 containers. You calculate the sample average to be 6.43 lb. with a standard deviation of .14 lb. At the 0.02 level of significance, is the manufacturer correct?

QUESTION 28 "For a population with a mean = 440 and a standard deviation = 110, what is the X value corresponding to z = 2.67? (Be sure to round answer to the second decimal place)."

Suppose that SAT scores among U.S. college students are normally distributed with a mean of 500 and a standard deviation of 100. What is the probability that a randomly selected individual from this population has an SAT score between 500 and 600? 0.1587 0.3173 0.4207 0.3413

The Philadelphia office of Price Waterhouse Coopers LLP hired five accounting trainees this year. Their monthly starting salaries were: $3,536; $3,173; $3,448; $3,121; and $3,622. (I) Compute the population mean. (II) Compute the population variance. (III) Compute the population standard deviation. (IV) The Pittsburgh office hired six trainees. Their mean monthly salary was $3,550, and the standard deviation was $250. Compare the two groups

Please provide steps by step answer with proper explanation with final answer

For a population with a mean of 75 and a standard deviation of 12, what proportion of sample means of size n = 16 fall below 82?

A large milling machine produces steel rods to certain specifications. The machine is considered to be running normally if the standard deviation of the diameter of the rods is at most 0.42 millimeters. The line supervisor needs to test the machine is for normal functionality. The quality inspector takes a sample of 45 rods and finds that the sample standard deviation is 0.49. What is the test statistic? Select one: а. 59.89 b. 48.63 с. 50.50 d. 52.45

Question of the day: A machine is designed to produce insulating washers for electrical devices of average thickness of 0.025 cm. A random sample of 10 washers was found to have an average thickness of 0.024 cm with a standard deviation of 0.002 cm. Test the significance of the deviation. Value of t for 9 degrees of freedom at 5% level is 2.262?

You hope to rent an unfurnished one-bedroom apartment in Dallas next year. You call a friend who lives there and ask him to give you an estimate of the mean monthly rate. Having recently taken a statistics course, your geeky friend asks about the desired margin of error and confidence level for the estimate. He also tells you that the standard deviation of monthly rents for one-bedrooms is $360. Explain why in either case your geeky friend's sample may result in a bigger margin of error than desired. A bigger margin of error might result due to O rounding O a smaller guessed value for the population standard deviation sg O smaller confidence interval O a larger sample size

7. It is well known that car buyers often add accessories to their new cars. A sample of 179 Ottawa purchasers yielded a sample mean of $5000 worth of accessories added to the purchase above the base sticker price. Suppose the cost of accessories purchased for all Ottawa has a standard deviation of $1500. (a) Calculate a 95% confidence interval for the average cost of accessories on Ottawa. - Section Break - (b) Determine the margin of error in estimating the average cost of accessories on Ottawa. (c) What sample size would be required to reduce the margin of error by 50%?

In 2008, SAT math scores were normally distributed with a mean of 522 and a standard deviation of 102. What percentage of test takers scoree between 420 and 624 on the math portion? 0.3173 0.6587 0.3413 0.6827

Suppose a baker wants to know, on average, how many pastries they sell in a day. They sampled over 4 days. On the first day they sold 10, on the second day they sold 12, on the third day they sold 18, and on the fourth day they sold 16. The population standard deviation of pastry sales is 3. What is the point estimate (average) number of pastries sold? 26 08 056 O 14 Nex

ou would like to get the highest paying job possible after graduating from UCR and are currently deciding vhether to enroll in ECON 108 in the fall term or not. You find a sample of recent UCR graduates that majc n Economics (there are no double majors in the samples). You sampled 100 Economics majors that took ECON 108 and you find that the average starting salary is 72K dollars, with a sample standard deviation of 10K dollars. You sampled 75 Economics majors that did not take ECON 108 and you find that the average starting salary is 65K dollars, with a sample standard deviation of 15K dollars. Which of the following statements is most correct? O I am not very confident in the results of my hypothesis test because the range in which I fail to reject the null hypothesis is relatively large. O I want to be very confident in the results of my hypothesis test, so the range in which I fail to reject the null hypothesis is relatively large. O The range in which I fail to reject is small, so…

Suppose it is known that in a certain large human population cranial length is approximately normally distributed with a mean of 185.6 mm and a standard deviation of 12.7 mm. A random sample of size 10 from this population will have a mean greater than 190 with a=0.05 ? let Z-tabulate = 1.96 and T-tabulate= 2.30

A health expert evaluates the sleeping patterns of adults. Each week she randomly selects 40 adults and calculates their average sleep time. Over many weeks, she finds that 5% of average sleep time is less than 3 hours and 5% of average sleep time is more than 3.4 hours. What are the mean and standard deviation (in hours) of sleep time for the population? (Round "Mean" to 1 decimal places and "standard deviation" to 3 decimal places.) Mean Standard deviation

SCENARIO 3 Two samples each of size 25 are taken from independent populations assumed to be normally distributed with equal variances. The first sample has a mean of 35.5 and a standard deviation of 3.0 while the second sample has a mean of 33.0 and a standard deviation of 4.0. Referring to Scenario 3. the pooled (i.e., combined) variance is ________

A group of local businessmen is thinking about developing land into a shopping mall. To evaluate the desirability of the location, they count the number of shoppers who visit the neighboring shopping center each day. A random sample of 54 days reveals a daily average of 126 shoppers with a standard deviation of 48 shoppers. The businessmen will develop the land if the average number of shoppers per day is more than 110. Based on the sample data, should the businessmen develop the land? Perform a hypothesis test and use a significance level of a = 0.10. Assume the population of the number of daily shoppers is approximately normally distributed. Step 2 of 3: Compute the value of the test statistic. Round your answer to three decimal places.

A magazine conducts an annual survey in which readers rate their favorite cruise ship. All ships are rated on a 100-point scale, with higher values indicating better service. A sample of 33 ships that carry fewer than 500 passengers resulted in an average rating of 85.59, and a sample of 44 ships that carry 500 or more passengers provided an average rating of 81.40. Assume that the population standard deviation is 4.55 for ships that carry fewer than 500 passengers and 3.97 for ships that carry 500 or more passengers. A) What is the point estimate of the difference between the population mean rating for ships that carry fewer than 500 passengers and the population mean rating for ships that carry 500 or more passengers? (Use smaller cruise ships − larger cruise ships.)   (b) At 95% confidence, what is the margin of error? (Round your answer to two decimal places.)   (c) What is a 95% confidence interval estimate of the difference between the population mean ratings for the two sizes of…

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You may need to use the appropriate appendix table or technology to answer this question. Studies show that massage therapy has a variety of health benefits and it is not too expensive. A sample of 14 typical one-hour massage therapy sessions showed an average charge of $58. The population standard deviation for a one-hour session is a - $5.5. (a) What assumptions about the population should we be willing to make if a margin of error is desired? We should be willing to make the assumption that the population is at least approximately uniform. We should be willing to make the assumption that the population is at least approximately normal. We should be willing to make the assumption that the population is at least approximately skewed right. We should be willing to make the assumption that the population is at least approximately bimodal. We should be willing to make the assumption that the population is at least approximately skewed left. (b) Using 95% confidence, what is the margin of…

The records kept by a large department store indicate that, in the past, weekly sales have averaged $5775. In order to increase sales, the store recently began an aggressive advertising campaign. After 15 weeks, sales average $6350 with standard deviation of $850. Should the store continue the advertising campaign? Set a = .05.

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You survey 5 members of a college class about how many hours they study each week: 12 hours, 18 hours, 7 hours, 3 hours, and 15 hours. The class has a total of 28 students. Based on the findings from the 5 students you interviewed, what is the standard deviation for the entire class? What is the range of hours you can expect students to study based on one standard deviation? (Hint: Think Normal Distribution Curve).

A survey conducted by the American automobile association show that a family of four spent an average of $215.60 per day while on vacation. It's supposed to sample of 64 families of four vacationing at Niagara Falls resulted in a sample mean of $256.45 per day and a sample standard deviation of $76.50

A simple random sample of 8 employees of a corporation provided the following information. Employee Age Gender 1 2 3 21 37 26 W M W 4 5 6 7 8 44 48 50 25 22 W W M M M (a) Determine the point estimate for the average age of all employees. (b) What is the point estimate for the standard deviation of the population? (Round your answer to four decimal places.) (c) Determine a point estimate for the proportion of all employees who are female.

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What do you mean by Sample Variance, Sample Standard Deviation,and Standard Error?

Scenario 38-5. Researchers are interested in the height of the average person in San Francisco, California. Using a random sample of 1,000 people, they find that the average height in the sample is 68 inches. (Hint: Be sure to calculate the Refer to Scenario 38-5. If the standard deviation of heights is 3 inches, we can be 95% confident that the true mean height of the population is between standard error of the estimate.) O O O O between 67.997 inches and 68.003 inches. between 67.905 inches and 68.095 inches. between 67.905 inches and 68 inches. between 68 inches and 68.095 inches.

The mean was found to be u = 70 so now we need to find the standard deviation o. The standard deviation is calculated as follows where n is the sample size, 350, and p is the probability of a success, 0.2. Find the standard deviation. V np(1 – p) O = V 350( )(1 – 0.2)

Suppose that for a random sample,  the mean is 4 and  the coefficient of variation is 87.5%  then the value of the standard deviation is equal to:Immersive Reader   2.5   3.5   4.5   3