Question

1)Oxygen demand is a term biologists use to describe the oxygen needed by fish and other aquatic organisms for survival. The Environmental Protection Agency conducted a study of a wetland area. In this wetland environment, the mean oxygen demand was μ = 9.7 mg/L with 95% of the data ranging from 6.3 mg/L to 13.1 mg/L. Let x be a random variable that represents oxygen demand in this wetland environment. Assume x has a probability distribution that is approximately normal. Use the 95% data range to estimate the standard deviation for oxygen demand. a) An oxygen demand below 8 indicates that some organisms in the wetland environment may be dying. What is the probability that the oxygen demand will fall below 8 mg/L? (Round your answer to four decimal places.) (b) A high oxygen demand can also indicate trouble. An oxygen demand above 12 may indicate an overabundance of organisms that endanger some types of plant life. What is the probability that the oxygen demand will exceed 12 mg/L? (Round your answer to four decimal places.)

2) Workers at a large toxic cleanup project are concerned that their white blood cell counts may have been reduced. Let x be a random variable that represents white blood cell count per cubic millimeter of whole blood in a healthy adult. Then μ = 7500 and σ ≈ 1750.† A random sample of n = 50 workers from the toxic cleanup site were given a blood test that showed x = 6760.
Compute P(x ≤ 6760). (Round your answer to four decimal places.)

3) Do you have a great deal of confidence in the advice given to you by your medical doctor? About 25% of all adult Americans claim they do have a great deal of confidence in their M.D.s. Suppose a random sample of n = 33 adults in a health insurance program are asked about their confidence in the medical advice their doctors give. Find the value _of.σ_p̂. (Round your answer for σ_p̂ to three decimal places.)

4)Suppose x has a distribution with μ = 31 and σ = 12. f random samples of size n = 16 are selected, If the original x distribution Suppose x has a distribution with μ = 31 and σ = 12. a) If random samples of size n = 16 are selected. Find P(27 ≤ x ≤ 32). (Round your answer to four decimal places.)

Answer 1

dear student, please post the question one at a time.

1) The 95% of the data are within the 2 standard deviations from the mean.

............(1)

............(2)

Subtracting (1) from (2)

a) The probability that the oxygen demand will fall below 8 mg/L =

b) the probability that the oxygen demand will exceed 12 mg/L? =