A health care professional wishes to estimate the birth weights of infants. How large a sample must be obtained if he desires to be 95% confident that the true mean weight is within 2 ounces of the sample mean? Assume the population standard deviation is 6 ounces

A quantitative data set has a size 50. At least how many observations lie within 3standard deviations to either side of the​ mean?

please answer the question in the photo. Thank you

To compare the dry braking distances from 30 to 0 miles per hour for two makes of automobiles, a safety engineer conducts braking tests for 35 models of Make A and 35 models of Make B. The mean braking distance for Make A is 42 feet. Assume the population standard deviation is 4.7 feet. The mean braking distance for Make B is 45 feet. Assume the population standard deviation is 4.4 feet. At a = 0.10, can the engineer support the claim that the mean braking distances are different for the two makes of automobiles? Assume the samples are random and independent, and the populations are normally distributed. Complete parts (a) rari rz (b) Find the critical value(s) and identify the rejection region(s). The critical value(s) is/are (Round to three decimal places as needed. Use a comma to separate answers as needed.)

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For a random sample of 10 men, the mean head circumferences are x-bar = 57.3 cm, and the sample standard deviation is s = 2cm. what is the standard error of the mean?

Levels of a certain enzyme in the blood have a mean value of 34.0 mg/mL and a standard deviation of 3.5 mg/mL.  Complete the following steps to determine what levels of the enzyme correspond to the top 20% of test results.   Are you calculating the top or bottom 20%? Answer So, which percentage needs to be converted to an area? Answer What is the area that you will look for in the table (four decimal places)? Answer What area will you actually use from the table (four decimal places)? Answer What is the z-score associated with that area (two decimal places)? Answer What is the cutoff level of the enzyme that corresponds to the top 20% of test results? (round to the nearest tenths)   Answer Are values lower or higher than that value also in the top 20%? Answer