# Mean + probability - practice problems

#### Number of problems found: 197

- Three dices

What is the probability that the sum of points 14 will be a roll of three dice (B, M, Z)? - Pass a test

The student has to pass a test that contains 10 questions. For each of them, he chooses one of 5 answers, with just one being correct. The student did not prepare for the test, so he chooses the answers at random. What are the probabilities that the stude - Nursing school

The following table shows 1000 nursing school applicants classified according to scores made on a college entrance examination and the quality of the high school from which they graduated, as rated by a group of educators: @TB@ Quality of High Schools S - Three robots

In a workshop, three robots, Q, R and S, are employed to make chairs Robot Q makes 25% of the chairs Robot R makes 45% of the chairs The remaining chairs are made by Robot S Evidence has shown that 2 percent of the chairs made by robot Q are d - School student

The probability that a school student has a skateboard is 0.34, the probability that he has a bicycle is 0.81 and the probability that he has a skateboard and a bicycle is 0.22. What is the probability that a randomly selected student has a skateboard or - Population variance

In a California community college, 60% of students will transfer to a college in the CSU system. The number of students in a sample who will transfer follows a binomial distribution. If 8 students are randomly selected, find the population variance σ² of - Sample Proportion

In a California community college, 60% of students will transfer to a college in the CSU system. The number of students in a sample who will transfer follows a binomial distribution. 400 students are randomly selected from the college and 224 of them will - Error rate

The exam has 6 questions. Students have an error rate of 20% and can have a maximum of 1 question wrong. What is the probability that they will succeed? - Suppose 4

Suppose that 14% of all steel shafts produced by a certain process are nonconforming but can be reworked (rather than having to be scrapped). Consider a random sample of 200 shafts, and let X denote the number among these that are nonconforming and can be - Rich retirement

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for government health care but who have no private hea - The vaccination

The vaccination coverage of the population is 80%. Unvaccinated make up 60% of all infected. What percentage are unvaccinated more likely to be infected? Consider N = 10,000 inhabitants and K = 1,000 infected. b. How many times more likely are unvaccinate - Mortality tables

Mortality tables enable actuaries to obtain the probability that a person at any age will live a specified number of years. Insurance companies and others use such probabilities to determine life-insurance premiums, retirement pensions, and annuity paymen - An aircraft

An aircraft manufacturing company has submitted bids on two separate airline contracts, A and B. The company feels that it has a 70% chance of winning contract A and a 25% chance of winning contract B. Furthermore, it believes that winning contract A is i - Binomial probability

What is the binominal probability that at least 4 of the 6 trials (n=6) are succeeded where φ = 0.50? - Dice 7

A standard number cube is tossed 210 times. What is a reasonable prediction for the number of times the number cube will land on a 5? - What fraction

What fraction of number 1 to 30 is prime? - And-or probabilities

P(A ) = 0.53, P(B) = 0.15, and P(A n B ) = 0.18. Find P(A U B ). Round approximations to two decimal places. - Draw a triangle

We have line segments with lengths of 3cm, 5cm, 6cm, 7cm and 9cm. What is the probability in % that if I randomly select three of them I will be able to draw a triangle? - The spinner

The spinner below is spun 12 times. It landed on I 4 times, II 7 times, and III 1 time. What is the difference between the experimental and theoretical probabilities of landing on the II? - Smoker male

For a person selected randomly from a certain population, events A and B are defined as follows. A = event the person is male B = event the person is a smoker. For this particular population, it is found that P(A ) = 0.53, P(B) = 0.15, and P(A n B ) = 0.1

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Looking for help with calculating arithmetic mean? Mean - practice problems. Probability - practice problems.