The mean alkalinity level of water specimens collected from the Han River in Seoul, Korea, is 50 milligrams per liter. (Environmental Science & Engineering, September 1, 2000.) Consider a random sample of 100 water specimens collected from a tributary of the Han River. Suppose the mean and standard deviation of the alkalinity levels for the sample are Xbar= 67.8 mg/L and s = 14.4 mg/L. Is there sufficient evidence to indicate that the population mean alkalinity level of water in the tributary exceeds 50 mg/L? Use significance level 0.05 a. State the null and alternate hypothesis b. Calculate the test statistic

Total plasma volume is important in determining the required plasma component in blood replacement therapy for a person undergoing surgery. Plasma volume is influenced by the overall health and physical activity of an individual. Suppose that a random sample of 45 male firefighters are tested and that they have a plasma volume sample mean of x = 37.5 ml/kg (milliliters plasma per kilogram body weight). Assume that ? = 7.80 ml/kg for the distribution of blood plasma. When finding an 99% confidence interval, what is the critical value for confidence level? (Give your answer to two decimal places.) zc =  (a) Find a 99% confidence interval for the population mean blood plasma volume in male firefighters. What is the margin of error? (Round your answers to two decimal places.) lower limitupper limitmargin of error (b) What conditions are necessary for your calculations? (Select all that apply.) n is large? is known? is unknownthe distribution of volumes is normalthe distribution of…

The boiling point of 16 samples of a certain brand of hydrogenated vegetable oil used in a fryer was collected, resulting in Xbar=152.1 degrees. Assume that the distribution of melting point is normal with o=3.20. If the boiling point is different than 150 degrees, then either the oil will be too hot and will burn food or it will be too cool and will not properly cook the food. Is the sample mean significantly different from the target of 150 degrees? Use alpha=0.01 Но: H1: Define critical (rejection) region(s): Calculate the appropriate test statistic: What decision do we make? What this decision means in terms of this problem?

Suppose that blood chlorine concentration (mmol/L) has a normal distribution with mean=98 and standard deviation=7. For a sample of n=40, what is the corresponding mean and standard deviation of the sampling distribution?

Low‑density lipoprotein, or LDL, is the main source of cholesterol buildup and blockage in the arteries. This is why LDL is known as "bad cholesterol." LDL is measured in milligrams per deciliter of blood, or mg/dL. In a population of adults at risk for cardiovascular problems, the distribution of LDL levels is normal, with a mean of 123123 mg/dL and a standard deviation of 4141 mg/dL. If an individual's LDL is at least 11 standard deviation or more above the mean, he or she will be monitored carefully by a doctor. What percentage of individuals from this population will have LDL levels 11 or more standard deviations above the mean? Use the 6868–9595–99.799.7 rule. (Enter your exact answer as a whole number.)

The mean score for first exam in your first organic chemistry class (section A) was 60, with a standard deviation of 5. Your score on the exam was 70. A. How many standard deviations above the mean is your score?

Suppose that you wish to estimate the difference between mean pH measurements of rainfalls in two different locations, one in relatively unpolluted area and the other in an area subject to heavy air pollution. You want to be 95% confident that the margin of error for the difference between mean pH of rainfalls in relatively unpolluted area and mean pH of rainfalls in an area subject to heavy air pollution will not exceed 0.1 pH. How many rainfalls (pH measurements) must be included in each sample? Assume that the variance of pH measurements in a relatively unpolluted area is equal to 2 = 20, and the variance of pH measurements in an area subject to heavy pollution is equal to 2 = 0.25, and samples will be of equal size (n = n₂ = n). 2 It is supposed that values of pH in rainfalls are normally distributed in polluted and unpolluted areas. The number of rainfalls (pH measurements) that must be included in each sample is

Total plasma volume is important in determining the required plasma component in blood replacement therapy for a person undergoing surgery. Plasma volume is influenced by the overall health and physical activity of an individual. Suppose that a random sample of 46 male firefighters are tested and that they have a plasma volume sample mean of x = 37.5 ml/kg (milliliters plasma per kilogram body weight). Assume that ? = 7.80 ml/kg for the distribution of blood plasma. When finding an 99% confidence interval, what is the critical value for confidence level? (Give your answer to two decimal places.) zc = (a) Find a 99% confidence interval for the population mean blood plasma volume in male firefighters. What is the margin of error? (Round your answers to two decimal places.) lower limitupper limitmargin of error (b) What conditions are necessary for your calculations? (Select all that apply.) n is largethe distribution of weights is normalthe distribution of weights is uniform? is…

A normal population has a mean  μ = 31 and standard deviation = 8. What proportion of the population is less than 29?