# Probability - practice problems

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: 336

- Bernoulli trial

A used car sales woman estimates that each times she shows a customer a car, there is a probability of 0.1 that the customer will buy the car. The sales woman would like to sell at least one car per week. If showing a car is a Bernoulli trial with a proba - There 25

There are four red marbles and six blue marbles in a bag. What is the probability of picking up one blue marble and then one red marble? (assume that you keep the blue marble out of the bag) - Conditional probability

Suppose a batch contains 10 items of which 4 are defective. Two items are drawn at random from the batch one after the other, without replacement. What is the probability that: I) both are defective? Ii) the second item is defective? - A fair coin

A fair coin is tossed twice. Write down the set of possible outcomes. What is the probability of obtaining? I. Exactly one head ii. No head - Probability 86

At a business conference, there were 10 social workers, 16 doctors, 5 lawyers, and 2 journalists. If a person is picked at random from the entire group, what it is probability: a) to be a lawyer b) to be a doctor. - Overbooking flight

A small regional carrier accepted 12 reservations for a particular flight with 11 seats. 7 reservations went to regular customers who will arrive for the flight. Each of the remaining passengers will arrive for the flight with a 49% chance, independently - A bag 4

A bag contains 18 balls that differ only in colour, 11 are blue and 7 red. If two balls are picked, one after the other without replacement, find the probability that both are (i) Blue (ii) Of the same colour (iii) Of different colours - Box of donuts

Elizabeth brought a box of donuts to share. There are two-dozen (24) donuts in the box, all identical in size, shape, and color. 6 are jelly-filled, 10 are lemon-filled, and 8 are custard-filled. You randomly select one donut, eat it, and select a - Z-score test

The weights of the fish in a certain lake are normally distributed with a mean of 11 lb and a standard deviation of 6. If 4 fish are randomly selected, what is the probability that the mean weight will be between 8.6 and 14.6 lb? Your answer should be a d - Three 192

Three separate containers each have one purple marble and two blue marbles. One marble is chosen from each box. Find the probability of choosing a blue marble from each box. - A six-sided

A six-sided die is rolled once. What is the probability that the number rolled is an even number greater than two? - The following

The following data represents the number of cases of coffee or filters sold by four sales reps in a recent sales competition. Sales Person; Gourmet; Single Cup; Filters; Total Connor; 142; 325; 30; 497 Paige ; 42; 125; 40; 207 Bryce ; 9; 100; - Prisoners

It is estimated that 10% of all federal prisoners have a positive self-image, 40% have a neutral self-image, and the rest have a negative self-image. The estimated probability of rehabilitating a prisoner with a negative self-image is 0.1. With a neutral - Probability 73714

I roll six six-sided dice; what is the probability that exactly three threes will fall? - Conditional 73664

I roll a 7-wall dice. What is the conditional probability that three fell if an odd number fell? - Probability 73654

We roll two dice. One is 6-walled, and the other is 8-walled. What is the probability that at least one unit will fall? - How many 23

How many times should a dice be rolled to obtain a most likely number of 2 points on it to be equal to 32? - Suppose 6

Suppose the life span of a revolutionary light bulb is normally distributed with a mean life span of 70 thousand hours and a standard deviation of 3 thousand hours. If a light bulb is chosen at random: a) what is the probability the life span will be with - 20 balls

20 coloured balls in a bag 4 red 7 green 9 yellow What is the probability of picking a yellow ball? - Probability 73054

We roll six dice. What is the probability that: a) a six falls twice b) six falls four times

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