MATH 533 Week 4 Quiz (Summer 2019)
- Question 6.2.4: A random sample of 89 observations produced a mean x̄ = 25.7 and a standard deviation s = 2.5.
- Question 6.5.67: A company wants to test a randomly selected sample of n water specimens and estimate the mean daily rate of pollution produced by a mining operation. If the company wants a 95% confidence interval estimate with a margin of error of 1.6 milligrams per liter (mg/L), how many water specimens are required in the sample? Assume prior knowledge indicates that pollution readings in water samples taken during a day are approximately normally distributed with a standard deviation equal to 7 mg/L.
- Question 6.2.19: Each child in a sample of 65 low-income children was administered a language and communication exam. The sentence complexity scores had a mean of 7.61 and a standard deviation of 8.95. Complete parts a through
- Question 6.4.53-T: Environmental engineers are using data … by weather data centers to learn how climate affects the sea ice. Of 513 ice melt ponds studied in a certain region, 76 were classified as having “first-year ice”. The researchers estimated that about 15% of melt ponds in the region have first-year ice. Estimate, with 90% confidence, the percentage of all ice-melt ponds in the region that have first-year ice. Give a practical interpretation of the results.
- Question 6.3.35-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 meter) were measured at 20 randomly selected road sites. These values are … in the accompanying table. Complete parts a through
- Question 6.5.61: Suppose you wish to estimate a population mean correct to within 0.14 with a confidence level of .90. you don’t know σ2, but you know that the observations will range in value between 37 and 45. Complete parts a through b.
- Question 6.4.53-T: Environmental engineers are using data … by weather data centers to learn how climate affects the sea ice. Of 543 ice melt ponds studied in a certain region, 99 were classified as having “first-year ice”. The researchers estimated that about 18% of melt ponds in the region have first-year ice. Estimate, with 90% confidence, the percentage of all ice-melt ponds in the region that have first-year ice. Give a practical interpretation of the results.
- Question 6.3.35-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 meter) were measured at 20 randomly selected road sites. These values are … in the accompanying table. Complete parts a through
- Question 6.2.8: The mean and standard deviation of a random sample measurements are equal to 33.3 and 3.6 respectively.
- Question 6.2.21: The results of a study of 270 students who paid a private tutor to help them improve their scores on a standardized test are … below. The changes in both the Mathematics and verbal score for these students are reproduced in the table. Complete parts a through c below.
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