Probability Distributions Review

A coin is tossed 20 times and X is the number of heads which occur. Find the mean and variance of the X-distribution.

• Mean: 10, Variance: 5

• mean: 15, variance: 6

• Mean: 10, Variance: 6

• Mean: 10, Variance: 4

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CCSS.HSS.MD.A.2

An airline is interested in measuring the customer satisfaction of its passengers in all of its domestic flights on a certain day. The data analysis team took all 22 domestic flights of that day that took off from a certain airport. They randomly selected 25 passengers from each flight to form a sample of 550 passengers.

Which sampling technique did the data analysis team use?

• Stratified sampling

• Simple random sampling

• Quota sampling

• Systematic sampling

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CCSS.HSS.IC.B.3

Give a real-life example of systematic sampling.

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CCSS.HSS.IC.B.3

The values on the Venn-diagram below represent probabilities.

Find the value of x.

Write your answer as an exact decimal.

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CCSS.HSS.CP.A.1

Five different fair coins are tossed.

What is the probability that we see at least one head when we look at the results?

Give your answer as a decimal rounded to 3 significant figures.

A political strategist surveyed 100 people asking their opinion about a new proposal. The results are summarized in the contingency table.

Find the probability that a person chosen at random is a man who approves of the proposal.

• 0.42

• 0.19

• 0.24

• 0.52

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CCSS.8.SP.A.4

Which of the following is a discrete numerical variable?

• The number of students in a class.

• The height of a person.

• The weight of a car.

• Distance between two cities.

Which one of the following variables is a continuous variable?

• The height of Year 12 students in a high school.

• The number of people on a bus.

• The score out of 90 for a test.

• The number of computers in a computer room in a school.

Which of the following could be the population of interest for a statistician to survey and draw a conclusion.

• The people that live in a city.

• The people that live in a certain ward of a city.

• The people that live on a certain street in a city.

• All of these.

The maths teacher in Alpha High School in the United States randomly asked 70 second-year students of the school to get their opinion about the way maths is being taught in their class.

Which of the following is correct about the sample and the population in this context?

• The population is all the second-year students in Alpha High School and the sample is the 70 second-year students that were surveyed.

• The population is all the second-year students in the high schools of the United States and the sample is the 70 second-year students that were surveyed.

• The population is all the second-year students in the high schools of the United States and the sample is all the second-year students in the Alpha High School.

• The population is all the high-school students in Alpha High School and the sample is the 70 second-year students that were surveyed.

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CCSS.7.SP.A.1

CCSS.HSS.IC.A.1