1 (1 point) The owner of a fish market determined that the average weight for a catfish is 3.2 pounds with a standard deviation of 0.8 pounds. Assuming the weights of catfish are normally distributed, the probability that a randomly selected catfish will weigh more than 4.4 pounds is... a b c d 0.0668 0.34 1 0.6 Question 2 (1 point) The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. What is the probability that a randomly selected student obtains a score between 80% and 90%? a b c d 0.9452 0.9726 0.0977 0.0274 Question 3 (1 point) The Standard Normal Distribution has a mean and standard deviation of... a (0, 0) b (0, 1) c d (1, 1) (1, 0) Question 4 (1 point) The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. What is the probability that a randomly selected student obtained a score that is greater than 80% on the mathematics examination? a b c d 0.9 0.3421 0.1251 1.15 Question 5 (1 point) The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. Given this information, what percentile does a score of 75% represent? a b c d The 22nd percentile The 78th percentile The 100th percentile The 50th percentile Question 6 (1 point) If a particular normal distribution has a mean of 150 and a standard deviation of 5, the value 135 has a Z score of... a b c d -3 +2 -2 +3 Question 7 (1 point) If a particular normal distribution has a mean of 150 and a standard deviation of 5, the value 160 is _____ standard deviations away from the mean? a b c d -1 +2 +1 -2 Question 8 (1 point) If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the point in the distribution in which 75.8% of the college students exceed when trying to find a parking spot in the library parking lot. a b 2.8 minutes 3.4 minutes c d 4.2 minutes 3.2 minutes Question 9 (1 point) The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. What percentage of students obtain scores that are 50% or lower? a b c d 12.5% 50% 0.9% 87% Question 10 (1 point) The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. What is the probability that a randomly selected student obtained a score that is less than 65% on the mathematics examination? a b c d 0.65 1 0.25 0.5 Question 11 (1 point) The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. What is the probability that a randomly selected student obtained a score that is less than 40% on the mathematics examination? a b c d 0.5 0.0274 0.9726 0.4 Question 12 (1 point) The owner of a fish market determined that the average weight for a catfish is 3.2 pounds with a standard deviation of 0.8 pounds. Assuming the weights of catfish are normally distributed, above what weight do 89.8% of the weights occur? a b c d 1.56 pounds 4.882 pounds 3.21 pounds 2.184 pounds Question 13 (1 point) The heights of all women between the ages of 25 and 30 are normally distributed with a mean of 61.6 inches and a standard deviation of 3.9 inches. The heights of all men are also normally distributed with a height of 70 inches and a standard deviation of 7 inches. What is percentage of women are taller than the average man? a 98% b c d 2.75% 0% 1.58% Question 14 (1 point) The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. Given this information, 99% of students taking the exam score between ___ and ___. a b c d 25% and 75% 52% and 78% 35% and 95% 13% and 65% Question 15 (1 point) The heights of all women between the ages of 25 and 30 are normally distributed with a mean of 61.6 inches and a standard deviation of 3.9 inches. The heights of all men are also normally distributed with a height of 70 inches and a standard deviation of 7 inches. What is the probability that a randomly selected woman is shorter than the average man? a b c 1 0.75 0.8849 d 0.9842 Question 1 (1 point) Which of the following is true? a The mean of the sampling distribution is always equal to the population mean b The standard deviation of the sampling distribution is always equal to the population standard deviation c d The shape of the sampling distribution is always approximately normal All of the above Question 2 (1 point) The Central Limit Theorem is important in statistics because... a For a large n, it says the population is approximately normal b For a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population c For any sized sample, it says the sampling distribution of the sample men is approximately normal d For any population, it says the sampling distribution of the sample mean is approximately normal, regardless of the sample size Question 3 (1 point) The standard error of the mean... a b c d Is never larger than the standard deviation of the population Decreases as the sample size increases Measures the variability of the mean from sample to sample All of the above Question 4 (1 point) The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with a mean of 3.2 pounds and standard deviation of 0.8 pounds. If a sample of 64 fish yields a mean of 3.4 pounds, what is the probability of obtaining a sample mean this large or larger? a b c d 0.0228 0.4987 0.0001 0.0013 Question 5 (1 point) Let X equal the percentage of people in T&T with a least one car. If it is known that 57% of people in T&T have at least one car, what is the standard error of the sampling distribution of X if a sample of 500 peope is taken? a b 43% 1.53% c 4.9% d 2.2% Question 6 (1 point) The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with a mean of 3.2 pounds and standard deviation of 0.8 pounds. If a sample of 16 fish is taken, what would the standard error of the mean weight equal? a b c d 0.003 0.2 0.8 0.05 Question 7 (1 point) If the expected value of a sample statistic is equal to the parameter it is estimating, then we call that sample statistic... a b c d Unbiased Random Minimum variance Biased Question 8 (1 point) An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is known to be $1,000. A random sample of 50 individuals resulted in an average income of $15,000. What is the upper end point of the 99% confidence interval for average income? a b c d $14,050 $16,000 $16,050 $15,330 Question 9 (1 point) According to the Pew Research Center, in 2014 63% of people were absolutely certain that God exists. What would be the margin of error of a 95% confidence interval if the sample size was 65? a b c d 5% 13% 10.8% 11.7% Question 10 (1 point) Which of the following is true? a b c The lower the level of confidence the larger the margin of error The smaller the sample size the larger the margin of error The larger the margin of error the more precise the estimate d The larger the sample size the larger the margin of error Question 11 (1 point) A 99% confidence interval estimate can be interpreted to mean that... a If all possible samples are taken and confidence interval estimates are developed, 99% of them would include the true population mean somewhere within their interval We have 99% confidence that we have selected a sample whose interval does include the population mean b c Both of the above None of the above d Question 12 (1 point) According to the Pew Research Center, in 2014 63% of people were absolutely certain that God exists. This finding was based on a sample of 35,071 people. Which of the following represents a 95% confidence interval? a b c d 63% 0.505% 37% 0.505% 63% 0.425% 63% 1.65% Question 13 (1 point) When the standard deviation of the population is not known but the population is known to be normally distributed which of the following tables should be used to create a confidence interval? a b c d The student's t distribution tables Chi-squared distribution tables The standard normal distribution tables The F distribution tables Question 14 (1 point) A researcher uses a particular Z score (Z) from the standard normal density function to create a 95% confidence interval. Which of the following statements is not true? a b c The area under the between -Z and +Z is equal to 0.95 The area under the curve to the right of +Z is equal to 0.025 The area under the curve to the left of -Z is equal to 0.975 d The area under the curve to the left of +Z is exactly equal to the area under the curve to the right of -Z Question 15 (1 point) A quality control engineer is interested in the mean length of sheet insulation being cut automatically by a machine. The desired length of the insulation is 12 feet. It is known that the standard deviation in the cutting length is 0.15 feet. A sample of 70 cut sheets yields a mean length of 12.14 feet. This sample will be used to obtain a 99% confidence interval for the mean length cut by the machine. What is the confidence interval? a b (12, 12.69) (12.1, 12.18) c d (11.56, 11.2) (11.02, 13.1)