Q #1

10. [-/1 Points] DETAILS BBUNDERSTAT12 7.R.010.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A research group conducted an extensive survey of 3156 wage and salaried workers on issues ranging from relationships with their bosses to household chores. The data were gathered through hour-long telephone interviews with a nationally representative sample. In response to the question, "What does success mean to you?" 1566 responded, "Personal satisfaction from doing a good job." Let p be the population proportion of all wage and salaried workers who would respond the same way to the stated question. How large a sample is needed if we wish to be 95% confident that the sample percentage of those equating success with personal satisfaction is within 2.5% of the population percentage? (Hint: Use p 2 0.50 as a preliminary estimate. Round your answer up to the nearest whole number.) LA USE SALT workers Need Help? Read It11. [-/1 Points] DETAILS BBUNDERSTAT12 7.R.011.5. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Three-circle, red-on-white is one distinctive pattern painted on ceramic vessels of the Anasazi period found at an archaeological site. At one excavation, a sample of 177 potsherds indicated that 64 were of the three-circle, red-on-white pattern. LO USE SALT (a) Find a point estimate p for the proportion of all ceramic potsherds at this site that are of the three-circle, red-on-white pattern. (Round your answer to four decimal places.) (b) Compute a 95% confidence interval for the population proportion p of all ceramic potsherds with this distinctive pattern found at the site. (Round your answers to three decimal places.) lower limit upper limit Need Help? Read It Watch It12. [-/1 Points] DETAILS BBUNDERSTAT12 7.R.012.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Three-circle, red-on-white is one distinctive pattern painted on ceramic vessels of the Anasazi period found at the Wind Mountain archaeological site. At one excavation, a sample of 170 potsherds indicated that 76 were of the three-circle, red-on-white pattern. How many ceramic potsherds must be found and identified if we are to be 95% confident that the sample proportion p of such potsherds is within 5.6% of the population proportion of three-circle, red-on-white patterns found at this excavation site? (Round your answer up to the nearest whole number.) LA USE SALT potsherds Need Help? Read It13. [0.34/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.R.013.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The following data represent soil water content (percent water by volume) for independent random samples of soil taken from two experimental fields growing bell peppers. Soil water content from field I: x1; n1 = 72 15.3 11.3 10.3 10.8 16.6 8.3 9.1 12.3 9.1 14.3 10.7 16.1 10.2 15.2 8.9 9.5 9.6 11.3 14.0 11.3 15.6 11.2 13.8 9.0 8.4 8.2 12.0 13.9 11.6 16.0 9.6 11.4 8.4 8.0 14.1 10.9 13.2 13.8 14.6 10.2 11.5 13.1 14.7 12.5 10.2 11.8 11.0 12.7 10.3 10.8 11.0 12.6 10.8 9.6 11.5 10.6 11.7 10.1 9.7 9.7 11.2 9.8 10.3 11.9 9.7 11.3 10.4 12.0 11.0 10.7 8.6 11.2 Soil water content from field II: x2; n2 = 80 12.3 10.2 13.6 8.1 13.5 7.8 11.8 7.7 8.1 9.2 14.1 8.9 13.9 7.5 12.6 7.3 14.9 12.2 7.6 8.9 13.9 8.4 13.4 7.1 12.4 7.6 9.9 26.0 7.3 7.4 14.3 8.4 13.2 7.3 11.3 7.5 9.7 12.3 6.9 7.6 13.8 7.5 13.3 8.0 11.3 6.8 7.4 11.7 11.8 7.7 12.6 7.7 13.2 13.9 10.4 12.9 7.6 10.7 10.7 10.9 12.5 11.3 10.7 13.2 8.9 12.9 7.7 9.7 9.7 11.4 11.9 13.4 9.2 13.4 8.8 11.9 7.1 8.6 14.0 14.5 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 $1 = *2 = 57 (b) Let My be the population mean for x1 and let My be the population mean for x2. Find a 95% confidence interval for M1 - #2. (Round your answers to two decimal places.) lower limit upper limit4. [0.5/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.R.014. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER How profitable are different sectors of the stock market? One way to answer such a question is to examine profit as a percentage of stockholder equity. A random sample of 25 retail stocks such as Toys 'R' Us, Best Buy, and Gap was studied for x1, profit as a percentage of stockholder equity. The result was x1 = 13.0. A random sample of 35 utility (gas and electric) stocks such as Boston Edison, Wisconsin Energy, and Texas Utilities was studied for x2. profit as a percentage of stockholder equity. The result was x2 = 9.9. Assume that 61 = 4.3 and 62 = 2.8. (a) Categorize the problem below according to parameter being estimated, proportion p, mean #, difference of means (1 - /2. or difference of proportions p1 - p2. Then solve the problem. Ou 1 1 - 12 O P1 - P2 (b) Let My represent the population mean profit as a percentage of stockholder equity for retail stocks, and let My represent the population mean profit as a percentage of stockholder equity for utility stocks. Find a 95% confidence interval for /1 - /2. (Use 1 decimal place.) lower limit upper limit (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, does it appear that the profit as a percentage of stockholder equity for retail stocks is higher than that for utility stocks? Because the interval contains only positive numbers, we can say that the profit as a percentage of stockholder equity is higher for retail stocks. Because the interval contains both positive and negative numbers, we can not say that the profit as a percentage of stockholder equity is higher for retail stocks. O We can not make any conclusions using this confidence interval. O Because the interval contains only negative numbers, we can say that the profit as a percentage of stockholder equity is higher for utility stocks. Need Help? Read ItSubmitted 15. [0.25/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.R.016.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A random sample of 22 wolf litters in Ontario, Canada, gave an average of x1 = 4.8 wolf pups per litter, with estimated sample standard deviation s1 = 1.2. Another random sample of 11 wolf litters in Finland gave an average of x2 = 2.6 wolf pups per litter, with sample standard deviation $2 = 1.4. LA USE SALT (a) Categorize the problem below according to parameter being estimated, proportion p, mean , difference of means /1 - /2. or difference of proportions p1 - p2. Then solve the problem. O P1 - P2 OH1 - H2 (b) Find an 95% confidence interval for /1 - /2, the difference in population mean litter size between Ontario and Finland. (Use 1 decimal place.) lower limit upper limit (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, does it appear that the average litter size of wolf pups in Ontario is greater than the average litter size in Finland? Because the interval contains only positive numbers, we can say that the average litter size of wolf pups is greater in Ontario. Because the interval contains both positive and negative numbers, we can not say that the average litter size of wolf pups is greater in Ontario. O We can not make any conclusions using this confidence interval. O Because the interval contains only negative numbers, we can say that the average litter size of wolf pups is greater in Finland. Need Help? Read ItSubmitted 16. [0.5/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.R.017.5. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A study considered the question, "Are you a registered voter?" Accuracy of response was confirmed by a check of city voting records. Two methods of survey were used: a face-to-face interview and a telephone interview. A random sample of 85 people were asked the voter registration question face to face. Of those sampled, seventy respondents gave accurate answers (as verified by city records). Another random sample of 80 people were asked the same question during a telephone interview. Of those sampled, seventy-five respondents gave accurate answers. Assume the samples are representative of the general population. LA USE SALT (a) Categorize the problem below according to parameter being estimated, proportion p, mean #, difference of means /1 - /2, or difference of proportions p1 - p2. Then solve the problem. O M1 - 12 O P1 - P2 (b) Let p1 be the population proportion of all people who answer the voter registration question accurately during a face-to-face interview. Let py be the population proportion of all people who answer the question accurately during a telephone interview. Find a 99% confidence interval for p1 - p2. (Use 3 decimal places.) lower limit upper limit (c) Does the interval contain numbers that are all positive? all negative? mixed? Comment on the meaning of the confidence interval in the context of this problem. At the 99% level, do you detect any difference in the proportion of accurate responses from face-to-face interviews compared with the proportion of accurate responses from telephone interviews O Because the interval contains only positive numbers, we can say that there is a higher proportion of accurate responses in face-to-face interviews. Because the interval contains both positive and negative numbers, we can not say that there is a higher proportion of accurate responses in face-to-face interviews. We can not make any conclusions using this confidence interval. Because the interval contains only negative numbers, we can say that there is a higher proportion of accurate responses in telephone interviews. Need Help? Read It Watch it17. [0.25/1 Points] DETAILS PREVIOUS ANSWERS BBUNDERSTAT12 7.R.018.5. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER From public records, individuals were identified as having been charged with drunken driving not less than 6 months or more than 12 months from the starting date of the study. Two random samples from this group were studied. In the first sample of 34 individuals, the respondents were asked in a face-to-face interview if they had been charged with drunken driving in the last 12 months. Of these 34 people interviewed face to face, 14 answered the question accurately. The second random sample consisted of 49 people who had been charged with drunken driving. During a telephone interview, 28 of these responded accurately to the question asking if they had been charged with drunken driving during the past 12 months. Assume the samples are representative of all people recently charged with drunken driving. LA USE SALT (a) Categorize the problem below according to parameter being estimated, proportion p, mean #, difference of means /1 - (2, or difference of proportions p1 - p2. Then solve the problem. OH OP O P1 - P2 O M1 - 12 (b) Let p1 represent the population proportion of all people with recent charges of drunken driving who respond accurately to a face-to-face interview asking if they have been charged with drunken driving during the past 12 months. Let py represent the population proportion of all people who respond accurately to the question when it is asked in a telephone interview. Find a 95% confidence interval for p1 - p2. (Use 3 decimal places.) lower limit upper limit (c) Does the interval found in part (a) contain numbers that are all positive? all negative? mixed? Comment on the meaning of the confidence interval in the context of this problem. At the 95% level, do you detect any differences in the proportion of accurate responses to the question from face-to- face interviews as compared with the proportion of accurate re es from telephone interviews? O Because the interval contains only positive numbers, we can say that there is a higher proportion of accurate responses in face-to-face interviews. Because the interval contains both positive and negative numbers, we can not say that there is a higher proportion of accurate responses in face-to-face interviews. We can not make any conclusions using this confidence interval. Because the interval contains only negative numbers, we can say that there is a higher proportion of accurate responses in telephone interviews. Need Help? Read it