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Submitted 8. [0.4/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.3.017.5. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHE For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. In a combined study of northern pike, cutthroat trout, rainbow trout, and lake trout, it was found that 26 out of 803 fish died when caught and released using barbless hooks on flies or lures. All hooks were removed from the fish. LO USE SALT (a) Let p represent the proportion of all pike and trout that die (i.e., p is the mortality rate) when caught and released using barbless hooks. Find a point estimate for p. (Round your answer to four decimal places.) (b) Find a 99% confidence interval for p. (Round your answers to three decimal places.) lower limit upper limitSubmitted 9. [0.34/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.3.018.5. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A random sample of 320 medical doctors showed that 166 had a solo practice. LA USE SALT (a) Let p represent the proportion of all medical doctors who have a solo practice. Find a point estimate for p. (Use 3 decimal places.) (b) Find a 98% confidence interval for p. (Use 3 decimal places.) lower limit upper limit Give a brief explanation of the meaning of the interval. O 2% of the all confidence intervals would include the true proportion of physicians with solo practices. 98% of the all confidence intervals would include the true proportion of physicians with solo practices. 98% of the confidence intervals created using this method would include the true proportion of physicians with solo practices. 2% of the confidence intervals created using this method would include the true proportion of physicians with solo practices. (c) As a news writer, how would you report the survey results regarding the percentage of medical doctors in solo practice? Report p along with the margin of error. Report the margin of error. Report p. O Report the confidence interval. What is the margin of error based on a 98% confidence interval? (Use 3 decimal places.) Need Help? Read itSubmitted 10. [0.34/1 Points] DETAILS PREVIOUS ANSWER BBUNDERSTAT12 7.3.020.5. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. In a marketing survey, a random sample of 1000 supermarket shoppers revealed that 272 always stock up on an item when they find that item at a real bargain price. LO USE SALT (a) Let p represent the proportion of all supermarket shoppers who always stock up on an item when they find a real bargain. Find a point estimate for p. (Round your answer to four decimal places.) (b) Find a 95% confidence interval for p. (Round your answers to three decimal places.) lower limit upper limit Give a brief explanation of the meaning of the interval. O We are 95% confident that the true proportion of shoppers who stock up on bargains falls within this interval. O We are 5% confident that the true proportion of shoppers who stock up on bargains falls above this interval. O We are 5% confident that the true proportion of shoppers who stock up on bargains falls within this interval. We are 95% confident that the true proportion of shoppers who stock up on bargains falls outside this interval. c) As a news writer, how would you report the survey results on the percentage of s at shoppers who stock up on items when they find the item is a real bargain? Report p. Report the confidence interval. Report p along with the margin of error. Report the margin of error. What is the margin of error based on a 95% confidence interval? (Round your answer to three decimal places.) Need Help? Read It11. [-/1 Points] DETAILS BBUNDERSTAT12 7.3.021.5. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. In a survey of 1000 large corporations, 256 said that, given a choice between a job candidate who smokes and an equally qualified nonsmoker, the nonsmoker would get the job. LO USE SALT a) Let p represent the proportion of all corporations preferring a nonsmoking candidate. Find a point estimate for p. (b) Find a 0.95 confidence interval for p. (Round your answers to three decimal places.) ower limit upper limit (c) As a news writer, how would you report the survey results regarding the proportion of corporations that would hire the equally qualified nonsmoker? O Report the margin of error. O Report P O Report p along with the margin of error. What is the margin of error based on a 95% confidence interval? (Round your answer to three decimal places.) Need Help? Read It12. [-/1 Points] DETAILS BBUNDERSTAT12 7.3.024.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. How hard is it to reach a businessperson by phone? Let p be the proportion of calls to businesspeople for which the caller reaches the person being called on the first try. LA USE SALT a) If you have no preliminary estimate for p, how many business phone calls should you include in a random sample to be 80% sure that the point estimate p will be within a distance of 0.06 from p? (Round your answer up to the nearest whole number.) phone calls b) A report states that businesspeople can be reached by a single phone call approximately 20% of the time. Using this (national) estimate for p, answer part (a). (Round your answer up to the nearest whole number.) phone calls Need Help? Read It13. [-/1 Points] DETAILS BBUNDERSTAT12 7.3.026.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. The National Council of Small Businesses is interested in the proportion of small businesses that declared Chapter 11 bankruptcy last year. Since there are so many small businesses, the National Council intends to estimate the proportion from a random sample. Let p be the proportion of small businesses that declared Chapter 11 bankruptcy last year. LA USE SALT (a) If no preliminary sample is taken to estimate p, how large a sample is necessary to be 99% sure that a point estimate p will be within a distance of 0.09 from p? (Round your answer up to the nearest whole number.) small businesses [b) In a preliminary random sample of 30 small businesses, it was found that nine had declared Chapter 11 bankruptcy. How many more small businesses should be included in the sample to be 99% sure that a point estimate p will be within a distance of 0.090 from p? (Round your answer up to the nearest whole number.) more small businesses Need Help? Read ItSubmitted 7. [0.22/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.4.014.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Independent random samples of professional football and basketball players gave the following information. Assume that the weight distributions are mound-shaped and symmetric. Weights (in lb) of pro football players: x1; nj = 21 247 261 255 251 244 276 240 265 257 252 282 256 250 264 270 275 245 275 253 265 272 Weights (in lb) of pro basketball players: x2; 02 = 19 202 200 220 210 192 215 221 216 228 207 225 208 195 191 207 196 182 193 201 LA USE SALT (a) Use a calculator with mean and standard deviation keys to calculate X1. $1. X2 and $2- (Round your answers to four decimal places.) * 1 * 2 = (b) Let My be the population mean for x1 and let /2 be the population mean for x2. Find a 99% confidence interval for (1 - M2. (Round your answers to one decimal place.) lower limit upper limit8. [0.34/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.4.016.MI.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The following data represent petal lengths (in cm) for independent random samples of two species of iris. Petal length (in cm) of Iris virginica: x ; n = 3 5.2 5.8 6.3 6.1 5.1 5.5 5.3 5 .5 6.9 5.0 4.9 6.0 4.8 6.1 5.6 5.1 5.6 4.8 5.4 5.1 5.1 5.9 5.2 5.7 4,5 6.4 5.3 5.5 6.7 5.7 4.9 4.8 5.9 5.1 5.1 Petal length (in cm) of Iris setosa: x,; n, = 38 1.6 1.6 1.4 1.5 1.5 1.6 1.4 1.1 1.2 1.4 1.7 1.0 1.7 1.9 1.6 1.4 1.5 1.4 1.2 1.3 1.5 1.3 1.6 1.9 1.4 1.6 1.5 1,4 1.6 1.2 1.9 1.5 1.6 1.4 1.3 1.7 1.5 1.5 LO USE SALT (a) Use a calculator with mean and standard deviation keys to calculate x1. $1. X2. and $2. (Round your answers to four decimal places.) 5 7 (b) Let M, be the population mean for x, and let /2 be the population mean for x2. Find a 99% confidence interval for 1 - M2. (Round your answers to two decimal places.) lower limit upper limitSubmitted 9. [0.34/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.4.017.5. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A random sample of 370 married couples found that 280 had two or more personality preferences in common. In another random sample of 574 married couples, it was found that only 24 had no preferences in common. Let p, be the population proportion of all married couples who have two or more personality preferences in common. Let P2 be the population proportion of all married couples who have no personality preferences in common. LO USE SALT (a) Find a 95% confidence interval for P1 - P2. (Use 3 decimal places.) lower limit upper limit (b) Explain the meaning of the confidence interval in part (a) in the context of this problem. Does the confidence interval contain all positive, all negative, or both positive and negative numbers? What does this tell you (at the 95% confidence level) about the proportion of married couples with two or more personality preferences in common compared with the proportion of married couples sharing no personality preferences in common? Because the interval contains only positive numbers, we can say that a higher proportion of married couples have two or more personality preferences in common. Because the interval contains both positive and negative numbers, we can not say that a higher proportion of married couples have two or more personality preferences in common. We can not make any conclusions using this confidence interval. Because the interval contains only negative numbers, we can say that a higher proportion of married couples have no personality preferences in common. Need Help? Read it Watch itSubmitted 10. [0.34/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.4.019. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The U.S. Geological Survey compiled historical data about Old Faithful Geyser (Yellowstone National Park) from 1870 to 1987. Let x, be a random variable that represents the time interval (in minutes) between Old Faithful eruptions for the years 1948 to 1952. Based on 8840 observations, the sample mean interval was x, = 62.8 minutes. Let x, be a random variable that represents the time interval in minutes between Old Faithful eruptions for the years 1983 to 1987. Based on 24,170 observations, the sample mean time interval was x2 = 71.4 minutes. Historical data suggest that , = 9.05 minutes and 62 = 12.55 minutes. Let /, be the population mean of x, and let /2 be the population mean of x2. (a) Compute a 90% confidence interval for My - (2. (Use 2 decimal places.) lower limit upper limit (b) Comment on the meaning of the confidence interval in the context of this problem. Does the interval consist of positive numbers only? negative numbers only? a mix of positive and negative numbers? Does it appear (at the 90% confidence level) that a change in the interval length between eruptions has occurred? Many geologic experts believe that the distribution of eruption times of Old Faithful changed after the quake that occurred in 1959. Because the interval contains only positive numbers, we can say that the interval length between eruptions has gotten shorter. Because the interval contains both positive and negative numbers, we can not say that the interval length between eruptions has gotten longer. We can not make any conclusions using this confidence interval. Because the interval contains only negative numbers, we can say that the interval length between eruptions has gotten longer. Need Help? Read It Watch it