Questions asked
Himani Sood
Numerade educator
Starting salaries of 50 college graduates who have taken a statistics course have a mean of $43,496 and a standard deviation of $9,264. Using 99% confidence, find both of the following: A. The margin of error E
T. L.
Module 15 Inference About A Population Mean Confidence Intervals Problem 5 (1 point) The scientific productivity of major world cities was the subject of a recent study. The study determined the number of scientific papers published between 1994 and 1997 by researchers from each of the 20 world cities, and is shown below. City | Number of papers | City | Number of papers City 1 | 13 | City 11 | 27 City 2 | 8 | City 12 | 8 City 3 | 24 | City 13 | 20 City 4 | 7 | City 14 | 21 City 5 | 30 | City 15 | 9 City 6 | 22 | City 16 | 8 City 7 | 12 | City 17 | 8 City 8 | 6 | City 18 | 22 City 9 | 7 | City 19 | 7 City 10 | 6 | City 20 | 20 Construct a 95 % confidence interval for the average number of papers published in major world cities. < ? < Note: You can earn partial credit on this problem.
Jeff Vermeire
Module 15 Inference About A Population Mean Problem 4 (1 point) The following random sample was selected from a normal distribution: 8 15 13 13 10 5 9 5 12 4 (a) Construct a 90% confidence interval for the population mean ?. ? ? ? (b) Construct a 95% confidence interval for the population mean ?. ? ? ? Note: You can earn partial credit on this problem.
Weights of 10 red and 36 brown randomly chosen M&M plain candies are listed below. Red: 0.897 0.923 0.882 0.913 0.983 0.891 0.871 0.924 0.913 0.907 0.897 0.875 0.985 0.861 0.913 0.93 0.914 0.871 0.931 0.877 0.988 0.898 0.856 0.909 0.931 0.876 0.928 0.918 Brown: 1.001 0.904 0.866 0.889 0.86 0.92 0.936 0.857 0.867 0.902 0.909 0.902 0.923 0.93 0.955 0.966 0.9 0.915 1. To construct a 90% confidence interval for the mean weight of red M&M plain candies, you have to use A. The t distribution with 11 degrees of freedom B. The t distribution with 10 degrees of freedom C. The t distribution with 9 degrees of freedom D. The normal distribution E. None of the above 2. A 90% confidence interval for the mean weight of red M&M plain candies is < ? < 3. To construct a 90% confidence interval for the mean weight of brown M&M plain candies, you have to use A. The normal distribution B. The t distribution with 37 degrees of freedom C. The t distribution with 36 degrees of freedom D. The t distribution with 35 degrees of freedom E. None of the above 4. A 90% confidence interval for the mean weight of brown M&M plain candies is < ? < Note: You can earn partial credit on this problem.
Suppose you have selected a random sample of n=14 measurements from a normal distribution. Compare the standard normal z values with the corresponding t values if you were forming the following confidence intervals. (a) 80% confidence interval
Paul A.
40 people are randomly selected and the accuracy of their wristwatches is checked, with positive errors representing watches that are ahead of the correct time and negative errors representing watches that are behind the correct time. The 40 values have a mean of 99 sec and a standard deviation of 221 sec. Use a 0.01 significance level to test the claim that the population of all watches has a mean of 0 sec. The test statistic is The P-Value is
Ana Carolina Da Cruz
Module 8 Normal Distribution: Problem 10 (1 point) The shelf life of a batteries produced by one major company are normally distributed with a mean of 3 years and a standard deviation of 1 years. The figure below shows the distribution of shelf lives of batteries produced by one major company. Calculate the shaded area under the curve. Express your answer in decimal form accurate to at least two decimal places. Answer:
David Nguyen
Shelia's doctor is concerned that she may suffer from gestational diabetes (high blood glucose levels during pregnancy). There is variation both in the actual glucose level and in the blood test that measures the level. A patient is classified as having gestational diabetes if the glucose level is above 140 milligrams per deciliter one hour after a sugary drink is ingested. Shelia's measured glucose level one hour after ingesting the sugary drink varies according to the Normal distribution with mean 128 mg/dl and standard deviation 10 mg/dl. Let L denote a patient's glucose level. (a) If measurements are made on three different days, find the level L such that there is probability only 0.03 that the mean glucose level of three test results falls above L for Shelia's glucose level distribution. What is the value of L?
Melissa Price
The distribution of actual weights of 8-oz chocolate bars produced by a certain machine is normal with mean 7.8 ounces and standard deviation 0.17 ounces. For a SRS of four of these chocolate bars, what is the level L such that there is a 4% chance that the average weight is less than L?
For a SRS of four of these chocolate bars, what is the level L such that there is a 4% chance that the average weight is less than L?