A z-score of -0.86 is a what percentile?

Fran would like to estimate the mean amount of time it takes people in her town to travel to work. the town's population is 150,000 and about 90,000 of those are working adults. which statements are true? select each correct answer. there is no way to infer the value of the mean. she must collect data for all 90,000 working adults and calculate the mean. a larger sample of working adults will provide a better estimate of the true mean than a smaller sample. the population of working adults is too large for using a sample to estimate the mean of the entire group. if she takes a random sample of the population of working adults in her town, the mean for that group is likely close to the mean for the entire group.

Pyotr tchaikovsky sporting goods operates on a 45% overhead based on the selling price, which results in an overhead of $65.34 on the newest version of an air hockey game set. if the air hockey game set costs pyotr tchaikovsky sports $49.32, find the selling price, the markup, and the net profit.

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