1. the mean incubation time for a type of fertilized egg kept at 100.5 degreesF IS 20 DAYs. suppose that the incubaton times are approximatley normally distributed with a standard deviation of 1 day.
a.what is the probability that a randomly selcted fertilized egg hatches in less than 19 days?
b.what is the probability that a randomly selcted fertilized egg takes over 21 days to hatch?
c.what is the probability that a randomly selcted fertilized egg hatches between 18 and 20 days?
d. would it be unusualfor ann egg to hatch in less than 17.5 days why?
find the indicated probability of the standard normal random variable Z.
P(-2.01 < or equal to Z< -1.09) =
3. find the Z score such that the area under the standard normal curve to the left is 0.95
4. A) compute Z1=19-20/3
C) THE AREA UNDER THE NORMAL CURVE BETWEEN X1=14 and x2=20 is 0.451. what is the area between z1 andz2?
c)the area is?
6. people were polled on how many books they read the previous year. ho many subjects are needed to estimate the number of books read the previous year within one book with a 90% confidence? initial survey results indicate that standARD DIVIATION EQUALS 14.3 BOOKS. 90% CONFIDENCE LEVEL REQUIRES how many SUBJECTs
7. a researcher wishes to estimate the average blood alchol concentration (BAC) for drivers involved in fatal accidents who are found to have positive BAC values. he randomly selects reecordsfrom 1400 suchh drivers and dtermind the smple mean BAC to be 0.16g/dl
(a) assuming that the populati0ion standard deviation for the BAC is 0.06 g/dl, construct an interperta 90% confidence interval for the mean BAC.
interpret a 90% confident inervalfor the mean bac. choose the correct answer. b. the researcher is 90% confident that the population mean bac is in the confidence interval for drivers involved in fatal accidents who have a positive bac value.
a. the researcher is 10% confident that the population mean bac is in the confidence interval involved in fatal accidents who have a positive bac value. c) the researcher is 90% confident that the population mean bac is not in the confidence interval for drivers involved in fatal accidents ho have a positive bac value..
(B) all states of a countryh use a bac of 0.10%g/dl as the legal intoxication level . is it possible that the mean bac of all drivers involved in fatal accidents who are found to have a positive bac values is less than the legal intoxication level? yes or no
8. steel rods are manufactured with a mean length of 29 cm. because of variability in the manufacturing process, the lengths of the rods are approximatley normally distributed with a standard deviation of 0.08 cm
(a) what proportion of rods has a length less than 28.9 cm?
(round to four decimal places as needed)
(b) any rods that are shorter than 28.83 cm or lonnger than 29.17 m are discarded. what proportion of rods will be discarded?
(c)using the results of part (b) if 5000 rods are manufactured in a day how many should the plant manager expet to discard?
(d) if an order comes in for 10,000 steel rods how many rods should the plant manager expect to manufacture if the order states that all rods must e between 28.9 cm and 29.1 cm
10. The shape of the didstribution of the time reguired to get an oil change at a 15-minute oil change facicility is unknown. however, records indicate that the mean time is 16.7 minutes, and thee standard deviation is 4.6 minnutes. (a) to compare probabilities regarding thr sample mean using the nnoral model, what ssize sample would be required? (b) what is the probability that a random sample of n=35
oil changes results in a sample mean time less than 15 minutes?
(a) choose the requred sample size: a. any sample size could be used. b.the sample size needs to be less than 30. c. the normal model cannot be used if the shape of the distribution is unknown. d. the sample size needs to be greaterr than 30.
the probability is approximatley?
10. suppose the length of the pregnancies of animals are approxiately normal distributed with the mean = 298 days and standrad deviation= 28 days.
(a) what is the probability of randomly selected pregnancy lasts less than 287 days?
(b) what is the porobability that a random sample of 18 pregnancies has a man gestation period of 287 days or less?
(c) what is the porbabilty that a random sample of 37 pregnancies has a mean gestation period of 287 days or less?
11. determine the area under the standard normal curve that lies to the right of (a)Z=0.83,(b)Z=-0.08,(c)Z=-1.88 and(d)Z=0.03
12. A SIMPLE RANDOM SAMPLE OF SIzE N=40 is drawn from a population. the sample mean is found to be x=120.5 and the sample standard deviation is found to be s=13.4 construct a 99% confidence interval for thepopulation mean. the lower bound is?
the upper bound is ?
14. a poll of 547adults fro a certain countryh employed full or part time asked "how uch total time in minutes do you spend commuting to and from work in a typical day?" survey results indicate that x=45.5 minutes and s=30.9minutes.complete a and b. a0construct and interpret a 90% confidence interval for the mean commute time of adult from this country emloyed full or part time.the lower bound is --- minutes. the upper bound is ----minutes.
interpret a 90% confidence interval for the mean commte time of adults employed full or part time. choose correct answer..a) there is a 90% confidence that ythe mean commute time of adults from this country, employed full or part time lies betweeen the lower and upper bounds of the interval.b)there is a 90% confidence that the mean commute time iis greater than the upper bound of the interval. c) there is 90% confidence that the mean commute time is less than the lower bound of the interval.
(b) is it possible that the mmean coute time is less than 40 min? yes or no
is it likely? yes or no
-sorry to send same problems with different nymbers but i had a time limit on my homework and missed it by 45 seconds. so it sht off, thank you. i also have one more set of 15 questions to send you but i cant until this is done.