Probability - practice problems - page 2 of 24
Probability is the measure of the likeliness that an event will occur. The probability (chance) is a value from the interval <0;1> or in percentage (0% to 100%) expressing the occurrence of some event. 0 is an impossible event, and 1 (100%) means the certainty event.Number of problems found: 464
- Bulb life
Tests show that the lives of light bulbs are normally distributed with a mean of 750 hours and a standard deviation of 75 hours. Find the probability that a randomly selected light bulb will last between 675 and 900 hours. - Five roommates
Five roommates will move into a house with four bedrooms: one double room and three single rooms. The five roommates propose that they draw names to determine the order in which they pick the bedrooms, assuming that the first three names drawn will choose - Ruben
Ruben owns a restaurant. He likes to keep track of everything customers are buying. His top 3 sellers are sandwiches, salads, and pizza. He knows that 1/3 of his customers buy a sandwich, 1/2 buy a salad, and 1/4 buy a pizza. What fraction of customers bu - A disease
A disease affects 10% of the individuals in a population, and a sample of 100 people was selected from the population. What is the probability of finding the disease in at least 15 people?
- Three sets
Of 240 students, 173 are on the honor roll, 48 are members of the varsity team, and 36 are on the honor roll and are also members of the varsity team. What is the probability that a randomly selected student is on the honor roll or is a member of the vars - A fair dice
A fair six-sided dice are rolled. What is the probability that the first number rolled is greater than 1 and the second number rolled is odd? Type your answer as a fraction in the simplest form. - Manufacturing company
It is established by the production manager of a manufacturing company that 2 out of every 20 units of a particular product are faulty. In a particular production hour, 8 units of the product were produced. Determine the probability that: (1) none of them - False positive, false negative
Suppose the likelihood of someone being allergic to cats is 1/1000 of the general population. A test to determine if you're allergic to cats has a false positive rate of 5%; that is, 5% of the time, the test will indicate incorrectly that you are allergic - So far
So far on its tour, a band sold out 3 shows and did not sell out the other 3 shows. Considering this data, how many of the band's next 4 shows would you expect to be sold out?
- Assume 2
Assume you are working with a standard six-sided die. What is the probability of rolling the die once and obtaining a 5 and then rolling the die again and obtaining a 2? (input 3 numbers after the decimal, do not round). Report probability as a proportion - A fair 2
A fair die is thrown two times. What is the probability that the sum of the score is almost 8? - The probability 2
The probability that an adult possesses a credit card is 0.71. A researcher selects two adults at random. The probability (rounded to three decimal places) that the first adult possesses a credit card and the second adult does not possess a credit card is - Repairs
A small repair shop orders parts for its repairs. Its supplier claims that only 2% of its parts are defective. In order of 500 parts, an employee takes a sample of 100 parts. Determine the likelihood that the employee finds three or more parts are defecti - 3 sigma
Students' performance scores in a statistic test have a mean of 70 and a standard deviation of 4.0. The scores obtained can be modeled by a normal distribution. Find the probability that the score of a randomly selected student is i. more than 80 marks ii
- Probabilities
The bag has 10 green, 6 yellow, and 4 blue. What are the probabilities as a fraction, decimals, and percents? - The profit 3
An investment's profit (or loss) is normally distributed with a mean of $11,200 and a standard deviation of $8,250. What is the probability of a loss rather than a profit? - Containers
One in eight containers is temporarily misplaced. A random sample of 12 containers is selected. What is the probability that 6 of these containers will be temporarily misplaced? - Testing students
Giving a test to a group of students, the grades and gender are summarized below. Grades and Gender ; A; B ; C ; Total Male; 20; 6; 19 ; 45 Female ; 17; 18; 13; 48 Total; 37; 24; 32; 93 If one student is chosen at random, a) Find the probability that the - Probability 83308
There are 10 parts in the box, 3 of them are defective. Let's choose 4 components at random. What is the probability that it will be among them a) 0 defective, b) just one defective component, c) just two defective components, d) exactly 4 defective compo
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