Question

A survey of 1000 adults asked that if they had paid for anything with cash during the previous 7 days. 432, or 43.2% said NO. Identify the bold numbers as parameter, statistic, or sample size. 1000 ___________________ 43.2% __________________

QUESTION 2 Jersey cows have a mean daily milk production of mu = 43 pounds. Assume this quantity has a Normal distribution with standard deviation of sigma = 5.5 pounds. a) Find the probability that a Jersey cow (one cow) will produce more than 50 pounds of milk in a day. b) A farmer has a herd of 25 Jersey cows. At the end of each day he records the average (per cow) milk production for that day, by weighing the day’s milk and dividing by 25. What is the mean and standard deviation of this average milk production for his herd? Note, n = 25 Mean = Standard deviation = c) What is the probability that the average milk production for his 25 cows exceeds 45 pounds on a given day, i.e., P( x with bar on top> 45)?

QUESTION 3 Most adults have been exposed to the cytomegalovirus (which causes mild, flu-like symptoms), and the low levels of virus that persists in the blood after infection can be extremely dangerous for infants who need transfusions. 20% of adults are “CMV-negative” (free of this virus), and their blood can be transfused into babies. If we take many different groups of 100 blood donors, the standard deviation of the (sample) proportions of CMV-negative donors would be close to which number?

A. 0.20

B. 0.2 x 0.8/ square root of 100= 0.016

C. square root of 100 x 0.2 x 0.8 end root equals 4

D. square root of fraction numerator 0.2 cross times 0.8 over denominator 100 end fraction end root equals 0.04

Answer 1