Unit Test — Unit test Answers

Four seniors and six juniors are competing for four places on a quiz bowl team.What is the approximate probability that all four seniors will be chosen at random?

A randomly generated password contains four characters. Each of the four characters is either a lowercase letter or a digit from 0–9. Each character in the password cannot be used more than once.What is the approximate probability that exactly one of the four characters will be a number?

There are 12 teams, each representing a different country, in a women’s Olympic basketball tournament. In how many ways is it possible for the gold, silver, and bronze medals to be awarded? Use the formula for permutations to find your answer.

Insurance company executives surveyed 200 young adults about their first motor vehicle. The results are shown in the two-way table.

Insurance company executives surveyed 200 young adults about their first motor vehicle. The results are shown in the two-way table.

A candle shop owner collected data on customers’ favorite scents, as shown in the table.LavenderVanillaCinnamonFloralCoconut0.310.180.23??

At the beginning of the semester, a professor tells students that if they study for the tests, then there is a 55% chance they will get a B or higher on the tests. If they do not study, there is a 20% chance that they will get a B or higher on the tests. The professor knows from prior surveys that 60% of students study for the tests. The probabilities are displayed in the tree diagram.

On a certain hole, a golfer knows that he has a 70% chance of reaching the green (putting surface) in one stroke, 20% in two strokes, 8% in three, and 2% in four or more. If he reaches the green on his first stroke, he has an 80% chance of putting the golf ball in the cup on his second stroke. If he does not reach the green on his first stroke, then he has a 30% chance of putting the golf ball in the cup on his second stroke. What is the probability that the golfer will reach the green in one stroke and put the ball in the cup on his second stroke?

A professional pool player claims that she sinks at least one ball in a pocket on 80% of her opening break shots. In a recent set of 20 games, she sunk at least one ball on her break shot in only 14 of the games. A simulation of 100 trials was conducted to see how unusual these most recent games are.

A standard deck of 52 cards contains 13 cards with hearts, 13 with diamonds, 13 with clubs, and 13 with spades. How many 7-card hands are possible with 2 hearts, 2 diamonds, 2 clubs, and 1 spade? Assume that the order of the cards does not matter, and use the formula for combinations to find your answer.

Shawn is playing a game with a set of cards. Half of them are blue and the other half are yellow. In the game, the player guesses the color of the top card, looks at the card, and returns the card to the deck. The player continues to do this, shuffling the deck after each guess.

A teacher offers gift cards as a reward for classroom participation. The teacher places the gift cards from four different stores into a bag and mixes them well. A student gets to select two gift cards at random (one at a time and without replacement). Each outcome in the sample space for the random selection of two gift cards is equally likely. What is the probability of each outcome in the sample space?

A researcher randomly surveyed 1,477 farmers to determine the geographical region in which they farm and the types of crops that grow there. The two-way table displays the data.Suppose a farmer from this survey is chosen at random. Let M = farmer lives in the Midwest and V = farmer grows vegetables. What is the value of P(V|M)?

Suppose that 71% of the surface of the Earth is covered in water, and a random number generator uses latitude and longitude to select a random location on the Earth. If 6 such locations are generated, what is the probability that all 6 locations are in water?

Suppose that 71% of the surface of the Earth is covered in water, and a random number generator uses latitude and longitude to select a random location on the Earth. If 7 such locations are generated, what is the probability that the first 5 locations are in water and the last 2 locations are on land?

The following two-way table shows the distribution of daily traffic and weather issues in a certain large city.

Five students want to play dodgeball and they all want to be a team captain. To be fair, the gym coach decides to place the names of all five students into a hat, mix well, and select two names at random without replacement. The names chosen will be the team captains. Each outcome in the sample space for the random selection of two team captains is equally likely. What is the probability of each outcome in the sample space?

In Canada, 63% of households speak English as their primary language, and 23% speak French as their primary language. If two Canadian households are selected at random, what is the probability that the first household speaks French, but the second household speaks English?

A study reported that about 40% of high school students have tried out for a sport at their school. To find out if this applies to Jessica’s school, she surveyed an SRS of 20 students. Nine of them said that they had tried out for a sport. To see if this result is surprising, a simulation is to be conducted to estimate the probability of obtaining a sample result as high as this one.Let 0–3 represent students who tried out for a sport and 4–9 represent students who did not try out for a sport.

A medical clinic is randomly selecting two staff members to attend a conference. The clinic employees include 7 nurses, 3 doctors, and 2 office staff. The nurses want to know the probability that both attendees will be nurses. The tree diagram displays the possible outcomes of randomly selecting two staff members.