please help with 22-32
22. [-/1 Points] DETAILS BBBASICSTAT8 7.TB. 108. MY NOTES For a normal distribution with u = 500 and o = 100, what is the minimum score necessary to be in the top 60% of the distribution? O 475 O 525 552 O 584 23. [-/1 Points] DETAILS BBBASICSTAT8 7.TB. 153. MY NOTES The distribution of sample means is the following. O is normal only if the population distribution is normal O is normal only if the sample size is greater than 30 O None of the other 3 choices are correct. O is always normal 24. [-/1 Points] DETAILS BBBASICSTAT8 7.TB. 159. MY NOTES If random samples, each with n = 9 scores, are selected from a normal population with / = 80 and o = 18, and the mean is calculated for each sample, then the average of all the sample means would be the following. cannot be determined without additional information O 80 0 6 0 2 25. [-/1 Points] DETAILS BBBASICSTAT8 8.TB.027. MY NOTES If all other factors are held constant, increasing the sample size will do the following. O decrease the width of the confidence interval O None of the other choices are correct. increase the standard error80 6 O2 25. [-/1 Points] DETAILS BBBASICSTAT8 8.TB.027. MY NOTES If all other factors are held constant, increasing the sample size will do the following. O decrease the width of the confidence interval O None of the other choices are correct. O increase the standard error O increase the width of the confidence interval 26. [-/1 Points] DETAILS BBBASICSTAT8 8.TB.030. MY NOTES If all other factors are held constant, which of the following would produce the smallest width for a confidence interval for u? O an 80% confidence interval based on a sample of n = 25 O a 90% confidence interval based on a sample of n = 100 O an 80% confidence interval based on a sample of n = 100 O a 90% confidence interval based on a sample of n = 25 27. [-/1 Points] DETAILS BBBASICSTAT8 8.TB.038. MY NOTES If all other factors are held constant, which confidence level will produce the smallest width for a confidence interval? 99% 60% O 75% O 90%28. [-l6 Points] BBBASICSTAT8 8.1.015.Ml. Allen's hummingbird (Selasphorus sasin) has been studied by zoologist Bill Alther.t Suppose a small group or 10 Allen's hummingbirds has been under study in Arizona. The average weight for these birds is Q = 3.15 grams. Based on previous studies, we can assume that the weights of Allen's hummingbirds have a normal distribution, with 17 = 0.25 gram. (a) Find an 80% confidence interval for the average weighs of Allen's hummingbirds in the study region. What is the margin of error? (Round your answers to two decimal places.) lower limit upper limit margin of error (b) What conditions are necessary for your calculations? (Select all that apply.) El n is large El 0 is unknown 1] unlfarm distribution of weights El normal distribution of weighs U a Is known (c) Interpret your results in the context of this problem. 0 We are 20% condent that the tme average weight of Allen's hummingbirds falls within this interval. 0 We are 80% condent that the true average weight of Allen's hummingbirds falls within this Interval. O The probability that this Interval contains the true average weight of Allen's hummingbirds is 0.30. O The probability that this interval contains the true average weight of Allen's hummingbirds is 020' (d) Find the sample size necessary for an 30% condenoe level with a maximal margin of error E = 0.14 for the mean weights of the hummingbirds. (Round up to the nearest whole number.) hummingbirds 29. [-/4 Points] BBBASICSTATS 8.R.008. Anystate Auto Insurance Company took a random sample of 372 insurance claims paid out during a 1year period. The average claim paid was $1545. Assume a = $252. Find a 0.90 condence interval for the mean claim payment, (Round your answers to two decimal places.) lower limit S upper limit 3 Find a 0.99 condence interval for the mean claim payment. (Round your answers to two decimal places.) lower limit s upper limit 3 30. [-/2 Points] DETAILS BBBASICSTAT8 8.R.006. MY NOTES Suppose you are told that a 95% confidence interval for the average price of a gallon of regular gasoline in your state is from $3.01 to $4.05. Use the fact that the confidence interval for the mean is in the form x - E to x + E to compute the sample mean and the maximal margin of error E. (Round your answers to two decimal places.) x = $ E = $ 31. [-/5 Points] DETAILS BBBASICSTAT8 8.3.011.MI.S. MY NOTES For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. In a random sample of 70 professional actors, it was found that 43 were extroverts. LA USE SALT (a) Let p represent the proportion of all actors who are extroverts. 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 two decimal places.) lower limit upper limit Give a brief interpretation of the meaning of the confidence interval you have found. O We are 5% confident that the true proportion of actors who are extroverts falls within this interval. We are 95% confident that the true proportion of actors who are extroverts falls within this interval. O We are 5% confident that the true proportion of actors who are extroverts falls above this interval. O We are 95% confident that the true proportion of actors who are extroverts falls outside this interval. (c) Do you think the conditions np > 5 and nq > 5 are satisfied in this problem? Explain why this would be an important consideration. O No, the conditions are not satisfied. This is important because it allows us to say that p is approximately binomial. O No, the conditions are not satisfied. This is important because it allows us to say that p is approximately normal. Yes, the conditions are satisfied. This is important because it allows us to say that p is approximately binomial. Yes, the conditions are satisfied. This is important because it allows us to say that p is approximately normal.(c) Do you think the conditions np > 5 and nq > 5 are satisfied in this problem? Explain why this would be an important consideration. O No, the conditions are not satisfied. This is important because it allows us to say that p is approximately binomial. No, the conditions are not satisfied. This is important because it allows us to say that p is approximately normal. Yes, the conditions are satisfied. This is important because it allows us to say that p is approximately binomial. O Yes, the conditions are satisfied. This is important because it allows us to say that p is approximately normal. 32. [-/5 Points] DETAILS BBBASICSTAT8 8.3.015.S. MY NOTES For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. A random sample of 5751 physicians in Colorado showed that 3251 provided at least some charity care (i.e., treated poor people at no cost). LA USE SALT (a) Let p represent the proportion of all Colorado physicians who provide some charity care. 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 limit Give a brief explanation of the meaning of your answer in the context of this problem. O We are 99% confident that the true proportion of Colorado physicians providing at least some charity care falls outside this interval. O We are 1% confident that the true proportion of Colorado physicians providing at least some charity care falls above this interval. O We are 1% confident that the true proportion of Colorado physicians providing at least some charity care falls within this interval. We are 99% confident that the true proportion of Colorado physicians providing at least some charity care falls within this interval. (c) Is the normal approximation to the binomial justified in this problem? Explain. O No; np > 5 and nq 5 and nq > 5. O No; np 5
