#18. To estimate the percentage of a species of rodent that carries a specific viral infection, 200 rodents are randomly selected and examined, and 106 of them are found to be infected. Based upon this find a 95% confidence interval for the proportion of all rodents of this species that are infected with the virus. Then find a lower and upper limit of the 95% confidence interval. Then give its lower limit and upper limit. Carry your intermediate computations to at least three decimal places and round your answers to two decimal place. Lower limit: Upper limit:

An ecologist randomly samples 13 plants of a specific species and measures their heights. He finds that this sample has a mean of 18 cm and a standard deviation of 4 cm. If we assume that the height measurements are normally distributed, find a 90% confidence interval for the mean height of all plants of this species. Then find the lower limit and upper limit of the 90% confidence interval. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit: |I| Upper limit:

From a large number of actuarial exam scores, a random sample of 275 scores is selected, and it is found that 206 of these 275 are passing scores. Based on this sample, find a 90% confidence interval for the proportion of all scores that are passing. Then complete the table below. Carry the intermediate computations to at least three decimal places. Round the answers to two decimal places.  (a)  What is the lower limit of the 90% confidence interval?   (b)  What is the upper limit of the 90% confidence interval?

A random sample of 225 adults was given an IQ test. It was found that 112 of them scored higher than 100. Based on this, compute a 90% confidence interval for the proportion of all adults whose IQ score is greater than 100. Then find the lower limit and upper limit of the 90% confidence interval.Carry your intermediate computations to at least three decimal places. Round your answers to two decimal places. Lower limit= Upper Limit=

The national average for the percentage of high school graduates taking the SAT is 49%, but the state averages vary from a low of 4% to a high of 92%. A random sample of 317 graduating high school seniors was polled across a particular tristate area, and it was found that 171 had taken the SAT. Estimate the lower boundary of the true proportion of high school graduates in this region who take the SAT with 95% confidence. Only the final answer should be rounded-off to THREE decimal places.

A random sample of ni = 270 people who live in a city were selected and 99 identified as a "dog person." A random sample of n2 = 108 people who live in a rural area were selected and 51 identified as a "dog person." Find the %3D 98% confidence interval for the difference in the proportion of people that live in a city who identify as a "dog person" and the proportion of people that live in a rural area who identify as a "dog person." Round answers to to 4 decimal places. < pi – P2 < -

A sample of size n=77 is drawn from a population whose standard deviation is 0= 33. Part 1 of 2 (a) Find the margin of error for a 95% confidence interval for µ. Round the answer to at least three decimal places. The margin of error for a 95% confidence interval for µ is Part 2 of 2 (b) If the confidence level were 90%, would the margin of error be larger or smaller? (Choose one) ▼ because the confidence level is (Choose one) ▼

An ecologist randomly samples 16 plants of a specific species and measures their heights. He finds that this sample has a mean of 17 cm and a standard deviation of 2 cm. If we assume that the height measurements are normally distributed, find a 99% confidence interval for the mean height of all plants of this species. Then find the lower limit and upper limit of the 99% confidence interval. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.

Suppose that administrators at a large urban high school want to gain a better understanding of the prevalence of bullying within their school. They select a random sample of 280 students who are asked to complete a survey anonymously. Of these students, 91 report that they have experienced bullying. Use this information to find a 95% z-confidence interval for p, the true proportion of students at this school who have experienced bullying. Give the limits (bounds) of the confidence interval as a proportion, precise to three decimal places. lower limit = upper limit =

A random sample of 375 bolts from machine A contained 26 defective bolts, while an independently chosen, random sample of 300 bolts from machine B contained 33 defective bolts. Let p, be the proportion of the population of all bolts from machine A that are defective, and let p, be the proportion of the population of all bolts from machine B that are defective. Find a 90% confidence interval for p, -p,. Then find the lower limit and upper limit of the 90% confidence interval. Carry your intermediate computations to at least three decimal places. Round your responses to at least three decimal places. (If necessary, consult a list of formulas.) Lower limit: Upper limit: