ECO 251CLT Test Questions And Answers Verified 100% Correct

ECO 251CLT Test Questions And Answers Verified 100% Correct The Central Limit Theorem requires . A) a sample size of at least 30 be used to ensure that the samples means are normally distributed B) the population be normally distributed to ensure that the samples means are normally distributed C) the bootstrap method to be used to select the sample D) the resampling technique to be used to select the sample -ANSWER A) a sample size of at least 30 be used to ensure that the samples means are normally distributed The Central Limit Theorem plays an important role in statistics because it provides information about the shape of the . A) population distribution when the sample size is sufficiently large B) sampling distribution when the sample size is sufficiently large C) population distribution for any sample size D) sampling distribution for any sample size -ANSWER B) sampling distribution when the sample size is sufficiently large As the size of the sample increases, the . A) standard error of the mean becomes smaller B) population standard deviation increases C) sampling error increases D) shape of the sampling distribution becomes wider -ANSWER A) standard error of the mean becomes smaller The process of recording information from the entire population is known as . A) collecting a sample B) resampling C) a bootstrap D) a census -ANSWER D) a census probability distribution. B) uniform The sampling distribution of the proportion follows the A) Poisson C) binomial D) exponential -ANSWER C) binomial According to the National Retail Federation, men spent an average of $484 over a recent Black Friday weekend. Assume that the standard deviation for this population is $146. A random sample of 42 men shoppers over this weekend was selected. What is the probability that the average amount spent on Black Friday weekend from this sample was less than $500? -ANSWER 0.7611 According to the National Retail Federation, women spent an average of $317 over a recent Black Friday weekend. Assume that the standard deviation for this population is $90. A random sample of 50 women shoppers over this weekend was selected. What is the probability that the average amount spent on Black Friday weekend from this sample was more than $300? -ANSWER 0.9099 According to the Labor Department, the average duration of unemployment for adults ages 20 to 24 was 34.6 weeks during a recent month. Assume that the standard deviation for this population is 10.2 weeks. A random sample of 36 adults in this age group was selected. What is the probability that the average duration of unemployment was between 31 and 35 weeks? -ANSWER 0.5778 According to Nielsen, the average smartphone owner used 606 megabytes of data per month. Assume that the standard deviation of data usage was 240 megabytes per month. A random sample of 60 smartphone users was selected. What is the probability that the average amount of data used in this sample was less than 580 megabytes? - ANSWER 0.2005 According to Strategic Vision, the average age of Mercedes buyers in the U.S. is 54 years old. Assume that the standard deviation for the age of these buyers is 8.5 years. A random sample of 38 Mercedes buyers was selected. What is the probability that the average age of these buyers is less than 56 years old? -ANSWER 0.9265 According to a report by Capital Economics, the average monthly mortgage payment in Chicago is $1,002. Assume that the standard deviation for monthly mortgage payments in Chicago is $168. To confirm these results, a random sample of 55 homeowners in Chicago was selected and found to have an average monthly mortgage payment of $1,030. Do the results of this survey support the report by Capital Economics? - ANSWER $1,046.37 - $957.63 Because 1,030 is between these limits, the results of this survey do support the report by Capital Economics. According to the Kaiser Family Foundation, the average annual premium paid by workers with employee-provided health insurance for family coverage was $4,129 in a recent year. Assume that the standard deviation for this annual premium is $560. To confirm these results, a random sample of 42 households with employee-provided health insurance was collected and found to have an average premium of $4,470 for family coverage. Determine the interval that contains 95% of the sample means from this sampling distribution and conclude whether or not this sample supports the findings of the Kaiser Family Foundation. -ANSWER $4,298.36 - $3,959.64 Because the sample mean $4,470 does not fall with this interval, the sample does not support the findings of the Kaiser Family Foundation. According to CTIA, the U.S. wireless industry handles more subscribers than any other country in the world, averaging 793 minutes per month per customer. Assume that the standard deviation for the number of minutes used per customer per month is 270. To confirm these results, a random sample of 65 wireless customers was selected and found to have a sample average of 822 minutes. Determine the interval that contains 95% of the sample means from this sampling distribution and conclude whether or not this sample supports the findings of CTIA. -ANSWER 858.6 minutes - 727.4 minutes Because the sample mean falls with this interval, the sample does support the findings of CTIA. According to a recent Catalyst Census, 16% of executive officers were women with companies that have company headquarters in the Midwest. A random sample of 125 executive officers from these companies was selected. What is the probability that more than 20% of this sample is comprised of female employees? -ANSWER 0.1112 A recent survey found that 86% of employees plan to devote at least some work time to follow games during the NCAA Men's Basketball Tournament. A random sample of 100 employees was selected. What is the probability that less than 80% of this sample will devote work time to follow games? -ANSWER 0.0418 Late flights for U.S. airlines are defined as those arriving 15 minutes later than the scheduled arrival. According to the Department of Transportation, 20.4% of domestic flights were late in a recent year. A random sample of 140 random domestic flights