The authors of a paper describe an experiment to evaluate the effect of using a cell phone on reaction time. subjects were asked to perform a simulated driving task while talking on a cell phone. while performing this task, occasional red and green lights flashed on the computer screen. if a green light flashed, subjects were to continue driving, but if a red light flashed, subjects were to brake as quickly as possible. the reaction time (in msec) was recorded. the following summary statistics are based on a graph that appeared in the paper.

n = 47
x = 525
s = 75

(a) construct a 95% confidence interval for μ, the mean time to react to a red light while talking on a cell phone. (round your answers to three decimal places.)
(b) suppose that the researchers wanted to estimate the mean reaction time to within 7 msec with 95% confidence. using the sample standard deviation from the study described as a preliminary estimate of the standard deviation of reaction times, compute the required sample size. (round your answer up to the nearest whole number.)

Overproduction of uric acid in the body can be an indication of cell breakdown. this may be an advance indication of illness such as gout, leukemia, or lymphoma.† over a period of months, an adult male patient has taken nine blood tests for uric acid. the mean concentration was x = 5.35 mg/dl. the distribution of uric acid in healthy adult males can be assumed to be normal, with σ = 1.87 mg/dl. (a) find a 95% confidence interval for the population mean concentration of uric acid in this patient's blood. 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.) σ is unknown n is large σ is known normal distribution of uric acid uniform distribution of uric acid (c) interpret your results in the context of this problem. there is not enough information to make an interpretation. the probability that this interval contains the true average uric acid level for this patient is 0.05. the probability that this interval contains the true average uric acid level for this patient is 0.95. there is a 95% chance that the confidence interval is one of the intervals containing the population average uric acid level for this patient. there is a 5% chance that the confidence interval is one of the intervals containing the population average uric acid level for this patient. (d) find the sample size necessary for a 95% confidence level with maximal margin of error e = 1.10 for the mean concentration of uric acid in this patient's blood. (round your answer up to the nearest whole number.) blood tests