For large U.S. companies, what percentage of their total income comes from foreign sales? A random sample of technology companies (IBM, Hewlett-Packard, Intel, and others) gave the following information.t Technology companies, % foreign revenue: x₁; n₁ = 16 62.8 55.7 47.0 59.6 55.3 41.0 53.4 50.8 65.1 39.3 44.6 49.4 61.2 48.5 Another independent random sample of basic consumer product companies (Goodyear, Sarah Lee, H.J. Heinz, Toys 'R' Us) gave the following information. X₁ = X1 $1 = *2 = $2 = 51.1 41.8 Basic consumer product companies, % foreign revenue: x2; n₂ = 17 28.0 30.5 34.2 50.3 11.1 40.7 60.1 23.1 21.3 42.8 32.5 28.8 40.0 18.0 36.9 44.9 28.0 USE SALT Assume that the distributions of percentage foreign revenue are mound-shaped and symmetric for these two company types. (a) Use a calculator with mean and standard deviation keys to calculate x₁, S₁, x2, and s2. (Round your answers to four decimal places.) % % % % (b) Let , be the population mean for x, and let ₂ be the population mean for x₂- Find a 95% confidence interval for ₁ - ₂- (Round your answers to two decimal places.) lower limit % upper limit O Because the interval contains only negative numbers, we can say that technology companies receive a lower percent of foreign revenue. O Because the interval contains only positive numbers, we can say that technology companies receive a higher percent of foreign revenue. O Because the interval contains both positive and negative numbers, we can not say that technology companies receive a higher percent of foreign revenue. (d) Which distribution (standard normal or Student's t) did you use? Why? O Student's t was used because ₁ and ₂ are known. O Standard normal was used because ₁ and ₂ are unknown. O Student's t was used because ₁ and 2 are unknown. O Standard normal was used because o, and d2 are known. MY NOTES (c) Examine the confidence interval and explain what it means in the context of this problem. Does the interval consist of numbers that are all positive? all negative? of different signs? At the 95% level of confidence, do technology companies have a greater percentage foreign revenue than basic consumer product companies? O We can not make any conclusions using this confidence interval. ASK YOUR TEACHER

For large U.S. companies, what percentage of their total income comes from foreign sales? A random sample of technology companies (IBM, Hewlett-Packard, Intel, and others) gave the following information.t Technology companies, % foreign revenue: x₁; n₁ = 16 62.8 55.7 47.0 59.6 55.3 41.0 53.4 50.8 65.1 39.3 44.6 49.4 61.2 48.5 Another independent random sample of basic consumer product companies (Goodyear, Sarah Lee, H.J. Heinz, Toys 'R' Us) gave the following information. X₁ = X1 $1 = *2 = $2 = 51.1 41.8 Basic consumer product companies, % foreign revenue: x2; n₂ = 17 28.0 30.5 34.2 50.3 11.1 40.7 60.1 23.1 21.3 42.8 32.5 28.8 40.0 18.0 36.9 44.9 28.0 USE SALT Assume that the distributions of percentage foreign revenue are mound-shaped and symmetric for these two company types. (a) Use a calculator with mean and standard deviation keys to calculate x₁, S₁, x2, and s2. (Round your answers to four decimal places.) % % % % (b) Let , be the population mean for x, and let ₂ be the population mean for x₂- Find a 95% confidence interval for ₁ - ₂- (Round your answers to two decimal places.) lower limit % upper limit O Because the interval contains only negative numbers, we can say that technology companies receive a lower percent of foreign revenue. O Because the interval contains only positive numbers, we can say that technology companies receive a higher percent of foreign revenue. O Because the interval contains both positive and negative numbers, we can not say that technology companies receive a higher percent of foreign revenue. (d) Which distribution (standard normal or Student's t) did you use? Why? O Student's t was used because ₁ and ₂ are known. O Standard normal was used because ₁ and ₂ are unknown. O Student's t was used because ₁ and 2 are unknown. O Standard normal was used because o, and d2 are known. MY NOTES (c) Examine the confidence interval and explain what it means in the context of this problem. Does the interval consist of numbers that are all positive? all negative? of different signs? At the 95% level of confidence, do technology companies have a greater percentage foreign revenue than basic consumer product companies? O We can not make any conclusions using this confidence interval. ASK YOUR TEACHER

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018

18th Edition

ISBN:9780079039897

Author:Carter

Publisher:Carter

Chapter10: Statistics

Section10.6: Summarizing Categorical Data

Problem 4AGP

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