The state highway department is studying traffic patterns on one of the busiest highways in the state. As part of the study, the department needs to estimate the average number of vehicles that pass an intersection each day. A random sample of 64 days gives us a sample mean of 14,205 cars and a sample standard deviation of 1,010 cars. What is the 92% confidence interval estimate of μ, the mean number of cars passing the intersection? Assume the population standard deviation is 1010. [14,028 14,382] [12,189 14,221] [14,183 14,227] [13,984 14,426]

Lucy recently switched her primary doctor to one specializing in caring for elderly patients. On her new doctor's website, it says that the mean systolic blood pressure among elderly females is 120 millimeters of mercury (mmHg). Lucy believes the value is actually higher. She bases her belief on a recently reported study of 19 randomly selected, elderly females. The sample mean systolic blood pressure was 132 mmHg, and the sample standard deviation was 24 mmHg. Assume that the systolic blood pressures of elderly females are approximately normally distributed. Based on the study, at the 0.05 level of significance, can it be concluded that μ, the population mean systolic blood pressure among elderly females, is greater than 120 mmHg? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) esc (a) State the null hypothesis H and the alternative hypothesis H₁. Ho: H₁:0 (b)…

Find the 90% confidence interval for the variance and standard deviation of the ages of students at Arcanum high school if a sample of 24 students has a standard deviation of 2.3 years. Assume the variable is normally distributed.

Assume that the heights of women are normally distributed. A random sample of 20 women have a mean height of 62.5 inches and a standard deviation of 1.3 inches. Construct a 98% confidence interval for the population variance, .

Two estimates are available for the same population parameter. Estimate one has a standard deviation of 8.5 and estimate two has a standard deviation of 8.7. Estimate two is unbiased, whereas estimate one is biased. Which estimate would you choose and why?

Suppose we wish to calculate a 90% confidence interval for the average amount spent on books by freshmen in their first year at a major university. The interval is to have a margin of error of $2. Assume that the amount spent on books by freshmen has a normal distribution with a standard deviation of $30. How many observations are required to achieve this margin of error?