A feed supply company has developed a special feed supplement to see if it will promote weight gain in livestock. Company researchers report that the 121 cows studied gained an average of 47 pounds and that a 95% confidence interval for the mean weight gain this supplement produces has a margin of error of ±8 pounds. Which of the following statements gives a valid interpretation of the 95% confidence interval? It is estimated that the mean weight gain of cows fed this supplement is between 39 and 55 pounds, and this estimation process is correct 95% of the time. If this supplement is tested on another sample of 121 cows there is a 95% chance that their average weight gain will be between 39 and 55 pounds. 95% of the 121 cows studied gained between 39 and 55 pounds. We are 95% sure that the average weight gain among the 121 cows in this study was between 39 and 55 pounds.

Health insurers and the federal government are both putting pressure on hospitals to shorten the average length of stay (LOS) of their patients. The average LOS in Canada is 4.6 days. A random sample of 18 hospitals in one province had a mean LOS of 3.8 days and a standard deviation of 1.7 days. Assume that the sampled population is approximately normal. You are to construct a 95% confidence interval to see if the population mean of 4.6 days is true. Answer the followings: a. What is/are the critical value(s)? b. What is the margin of error? c. Identify the 95% confidence interval for the mean. d. Interpret the interval in terms of this application. Circle the letter of the correct answer below. A. The state can be 95% confident that its mean LOS is within this interval. B. The state can be 5% confident that its mean LOS is within this interval. C. The state can be 95% confident that its mean LOS is outside this interval. D. The state can be 95% confident that its mean LOS is 3.8 days.…

A survey asked senior executives at large corporations their opinions about the economic outlook for the future. One question was, "Do you think that there will be an increase in the number of full-time employees at your company over the next 12 months?" In the current survey, 220 of 400 executives answered Yes, while in a previous year survey, 176 of 400 executives had answered Yes. Provide a 95% confidence interval estimate for the difference between the proportions at the two points in time. (Use current year − previous year. Round your answer to four decimal places.)  to

The Martin County Health Department needs to estimate the proportion of all children in the county aged 19-35 months that are completely up to date with all state-recommended immunizations. The Martin County Health Department found that 88% of a random sample of children in the county aged 19-35 months were completely up to date with all state-recommended immunizations. Find three different confidence intervals - one with sample size 228, one with sample size 402, and one with sample size 658. Assume that 88% of the children each sample are completely up to date with all state recommended immunizations. Observe how the sample size affects the margin of error and subsequently the width of each interval. Report confidence interval solutions using interval notation. Report all solutions in percent form, rounded to two decimal places, if necessary. • When n = 228, the margin of error for a 95% confidence interval is given by When n = • When n = When n = 228, a 95% confidence interval is…

The birth weights of a sample of newborns were recorded for a group born to mothers who did not get regular prenatal care (Group 1) and for a group born to mothers who did (Group 2). A 93% confidence interval for 41 – 2 was computed as follows: (-2.12 pounds, -0.89 pounds) Interpret the endpoints of this interval in the context of this problem. Do not use the word "difference" in your answer.

A study was conducted to estimate hospital costs for car accident victims who woreseat belts. Suppose that 46 randomly selected cases had an average of $15150and a standard deviation of $8500. If the average hospital costs for those that didnot wear seatbelts was $19000, construct a 90% confidence interval to see if theaverage costs are significantly different.

A recent provincial report states that 90% of the population is aware that piercings as well as tattoos can transmit infectious disease. A survey was conducted in the province and random subjects were asked if they knew that piercings as well as tattoos could transmit an infectious disease. Following this,  1450 people responded  with "yes" and 48 responded with "no".  Find the 95% confidence interval estimate of the proportion of those who know that  piercings as well as tattoos can transmit an infectious disease.

A trade magazine routinely checks the drive-through service times upper bound of 163.1 seconds. What does this mean? fast-food restaurants. An 80% confidence interval that results from examining 563 customers in one fast-food chain's drive-through has a lower bound of 159.5 seconds and an Choose the correct answer below. O A. One can be % confident that the mean drive-through service time of this fast-food chain is seconds O B. One can be % confident that the mean drive-through service time of this fast-food chain is between seconds and seconds. O C. The mean drive-through service time of this fast-food chain is seconds % of the time. O D. There is a % probability that the mean drive-through service time of this fast-food chain is between seconds and seconds.

It is estimated that in the general population about 9 out of every 1000 or 0.009 children are diagnosed with autism. on study included 92 six-month old babies who had a sibling with autism. twenty-eight of these babies were later diagnosed with autism. we will systematically construct a 99% confidence interval for the proportion of siblings of autistic children likely to have autism. what is the research question for this study? what is the correct symbol for the population parameter we are seeking to estimate? What is the proper notation for the observed test statistic for this study? What is the numerical value of the observed test statistic for this study? and whats the formula used?