MATH 533 Week 4 Homework Problems and Solutions (Summer 2019)
- Question 6.2.4: A random sample of 88 observations produced a mean x̄ =25.7 and a standard deviation s = 2.5.
- Question 2.8: The mean and standard deviation of a random sample of n measurements are equal to 34.4 and 3.7, respectively.
- Question 2.13: Based on a random sample of 1080 adults, the mean amount of sleep per night is 8.62 hours. Assuming the population standard deviation for amount of sleep per night is 1.7 hours, construct and interpret a 95% confidence interval for the mean amount of sleep per night.
- Question 3.27-T: The random sample shown below was selected from a normal distribution….. 7, 5, 6, 6, 8, 4
- Question 3.32: Periodically, a town water department tests the drinking water of hometown for contaminant such as lead. The lead levels in water specimens collected for a sample of 10 residents of the town had a mean of 2.6 mg/L and a standard deviation of 1.3 mg/L. complete parts a through c .
- Question 3.35-T: A group of researchers wants to estimate the true mean skidding distance along a new road in a certain forest. The skidding distances (in meters) were measured at 20 randomly selected road sites. These values are given in the accompanying table. Complete parts a through d.
- Question 4.48: A newspaper reported on the results of an opinion poll in which adults were asked what one thing they are most likely to do when they are home sick with a cold or the flu. In the survey, 65% said that they are most likely to sleep and 15% said that they would watch television. Although the sample size was not reported, typically opinion polls include approximately 1000 randomly selected respondents.
- Question 4.49: Suppose data collected by observers at randomly selected intersections across the country revealed that in a sample of 1000 drivers, 650 were using their cell phone.
- Question 5.60: If you wish to estimate a population mean with a margin of error ME = 0.33 using a 95% confidence interval and you know from prior sampling that σ2 is approximately equal to 4.7, how many observations would have to … included in your sample?
- Question 5.76: a company tests all new brands of golf balls to ensure that they meet certain specifications. One test conducted is intended to measure the average distance traveled when the ball is hit by a machine. Suppose the company wishes to estimate the mean distance for a new brand to within 1.6 yards with 95% confidence. Assume that past tests have indicated that the standard deviation of the distances the machine hits golf balls is approximately 11 yards. How many golf balls should … hit by the machine to achieve the desired accuracy in estimating the mean?
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