| Question 1 of 25 | 1.0 Points |
Which of the following statements is true regarding the data set 10, 10, 10, 10, and 10? | A.The range is zero | | B.The standard deviation equals zero | | C.The interquartile range equals zero | | D.all of the above | Reset Selection |
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| Question 2 of 25 | 1.0 Points |
If two events are mutually exclusive, what is the probability that one or the other occurs? | A.0.50 | | B.1.00 | | C.Cannot be determined from the information given. | | D.0.25 | Reset Selection | | Question 3 of 25 | 1.0 Points |
If two events are mutually exclusive, what is the probability that both occur at the same time? | A.Cannot be determined from the information given. | | B.1.00 | | C.0.00 | | D.0.50 | Reset Selection | |
| Question 4 of 25 | 1.0 Points |
If a gambler rolls two dice and gets a sum of 10, he wins $10, and if he gets a sum of three, he wins $20.The cost to play the game is $5.What is the expectation of this game? | A.$3.06 | | B.-$2.78 | | C.-$3.06 | | D.$2.78 | Reset Selection | | Question 5 of 25 | 1.0 Points |
One of the requirements for a binomial experiment is that there must be a(n) _____ number of trials. | A.odd | | B.random | | C.fixed | | D.infinite | Reset Selection | | Question 6 of 25 | 1.0 Points |
Suppose that 50 identical batteries are being tested. After 8 hours of continuous use, assume that a given battery is still operating with a probability of 0.70 and has failed with a probability of 0.30. What is the probability that greater than 40 batteries will last at least 8 hours? | A.0.4538 | | B.0.0402 | | C.0.9598 | | D.0.0789 | Reset Selection | |
| Question 7 of 25 | 1.0 Points |
If Z is a standard normal random variable, then the value z for which P(-z < Z < z) equals 0.8764 is | A.1.16 | | B.1.54 | | C.0.3764 | | D.3.08 | Reset Selection | | Question 8 of 25 | 1.0 Points |
The standard deviation of a probability distribution must be: | A.a negative number | | B.a nonnegative number | | C.less than the value of the mean | | D.a number between 0 and 1 | Reset Selection | | Question 9 of 25 | 1.0 Points |
Given that the random variable X is normally distributed with a mean of 80 and a standard deviation of 10, P(85 < X < 90) is | A.0.1498 | | B.0.3413 | | C.0.5328 | | D.0.1915 | Reset Selection | | Question 10 of 25 | 1.0 Points |
The average height of flowering cherry trees in a nursery is 11 feet.If the heights are normally distributed with a standard deviation of 1.6, find the probability that a randomly selected cherry tree in this nursery is less than 13 feet tall. | A.0.67 | | B.0.89 | | C.0.95 | | D.0.11 | Reset Selection | | Question 11 of 25 | 1.0 Points |
Find the probability, P(Z < 0.17), using the standard normal distribution. | A..8300 | | B..4325 | | C..5675 | | D..0675 | Reset Selection | | Question 12 of 25 | 1.0 Points |
The normal distribution is: | A.the single most important distribution in statistics | | B.a density function of a discrete random variable | | C.a discrete distribution | | D.a binomial distribution with only one parameter | Reset Selection | |
| Question 13 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A sample of 150 students at a State University was taken after the final business statistics exam to ask them whether they went partying the weekend before the final or spent the weekend studying, and whether they did well or poorly on the final.The following table contains the result. | | Did Well in Exam | Did Poorly in Exam | | Studying for Exam | 60 | 15 | | Went Partying | 22 | 53 | Of those in the sample who did well on the final exam, what percentage of them went partying the weekend before the exam? Place your answer in the blank, rounded to 2 decimal places. Do not use a percentage sign (%). For example, 44.44 would be a legitimate answer. |
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| Question 14 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. In a history class, students take a weekly multiple choice quiz consisting of 6 questions, each with 4 possible answers. If a student randomly guesses at the answer to each question for every quiz, then what is the mean number of correct answers the student will get on each quiz? Round your answer toone decimal place as necessary. For example, 4.5 would be a legitimate entry. Answer: | | Question 15 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Find the mean of the probability distribution: | X | 0 | 1 | 2 | 3 | 4 | | P(X) | 0.12 | 0.16 | 0.24 | 0.30 | 0.18 | Round your answer to two decimal place as necessary. For example, 4.56 would be a legitimate entry. Mean = | |
| Question 16 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Mothers Against Drunk Driving (MADD) is a very visible group whose main focus is to educate the public about the harm caused by drunk drivers.A study was recently done that emphasized the problem we all face with drinking and driving.Five hundred accidents that occurred on a Saturday night were analyzed.Two items noted were the number of vehicles involved and whether alcohol played a role in the accident.The numbers are shown below: Number of Vehicles Involved | Did alcohol play a role? | 1 | 2 | 3 | | | Yes | 60 | 110 | 30 | 200 | | No | 40 | 215 | 45 | 300 | | | 100 | 325 | 75 | | Given that 3 vehicles were involved, what proportion of accidents involved alcohol?Place your answer, roundedto 2 decimal places, in the blank.For example. 0.23 is a legitimate entry. | | Question 17 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. According to an Internet posting, 80% of adults enjoy drinking beer.If a group of 3 adults is selected at random, find the probability that none of them enjoy drinking beer. Place your answer,rounded to three decimal places, in the blank.When entering your answer do not use any labels or symbols other than a decimal point. Simply provide the numerical value.For example, 0.123 would be a legitimate entry. | |
| Question 18 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Scores on a mathematics examination appear to follow a normal distribution with mean of 65 and standard deviation of 15. The instructor wishes to give a grade of C to students scoring between the 60th and 70th percentiles on the exam. What score represents the 70th percentile score on the mathematics exam? Place your answer in the blank, rounded to a whole number. For example, 62 would be a legitimate entry. | | Question 19 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. The mean weight of loads of coal placed in train cars by a loading machine is 43.0 tons with a standard deviation of 8.0 tons. Assuming that the weight of loads placed in the train cars by this loader are normally distributed, if a random sample of 9 loads is chosen for a weight check, find the probability that the mean weight of those loads is more than 40.60 tons. Place your answer, rounded to four decimal places, in the blank.When entering your answer do not use any labels or symbols other than a decimal point. Simply provide the numerical value. For example, 0.1234 would be a legitimate entry. | | Question 20 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A Wendys fast-food restaurant sells hamburgers and chicken sandwiches. On a typical weekday, the demand for hamburgers is normally distributed with a mean of 450 and standard deviation of 80 and the demand for chicken sandwiches is normally distributed with a mean of 120 and standard deviation of 30. How many chicken sandwiches must the restaurant stock to be 99% sure of not running out on a given day? Place you answer, rounded to the nearest whole number in the blank. For example, 345 would be a legitimate entry. | | Question 21 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A popular retail store knows that the purchase amounts by its customers is a random variable that follows a normal distribution with a mean of $30 and a standard deviation of $9. What are the two dollar amounts, equidistant from the mean of $30, such that 98% of all customer purchases are between these values? Place your answers in the blanks provided. Do not include a dollar sign. For example, 14.25 would be a legitimate entry. Lower value Upper value | | Question 22 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. The average hourly wage of workers at a fast food restaurant is $6.50/hr with a standard deviation of $0.45. Assume that the distribution is normally distributed. If a worker at this fast food restaurant is selected at random, what is the probability that the worker earns more than $6.75? Place your answer, rounded to 4 decimal places, in the blank. For example, 0.1776 would be a legitimate entry. | | Question 23 of 25 | 1.0 Points |
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).NOTE:For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. It has been observed that electrical connectors manufactured by Jolt Electrical Supply Company last an average of 18.2 months and follow a normal distribution with a standard deviation of 1.7 months. Jolt agrees to replace any connector that fails within 19 months. Out of 500 connectors sold, how many does Jolt expect to replace, on average? Place your answer, rounded to the nearest whole number, in the blank. For example, 123 would be a legitimate answer. | |
| Question 24 of 25 | 1.0 Points |
A random variable X is normally distributed with a mean of 175 and a standard deviation of 50. Given that X = 150, its corresponding Z- score is 0.50. Reset Selection | | Question 25 of 25 | 1.0 Points |
If Z is a standard normal variable, then P(Z = 1) = 0.3413. Reset Selection | |
