Hon Geo 12.8-12.10 Assignment

A researcher wants to estimate the average length of all movies that were made in the last 10 years. To do so, they randomly select 25 movies that were made in the last 10 years, record the length of each of those movies, and calculate the average movie length. In this study, identify the sample and the population.

• Pop: all movies made in the last 10 year

  Sample: 25 randomly selected movies made in the last 10 years

• Pop: all movies ever made

  Sample: 25 randomly selected movies

• The sample and the population are the same.

• Pop: 25 randomly selected movies

  Sample: All movies ever made

Coach Manning measures the heights of a random sample of 5 members of the high school boy's basketball team. The average height is 73 inches. Which of the following claims is most reasonable?

• We are confident that the mean height of all students at this high school is close to 73 inches.

• We are confident that the mean height of all boys at this high school is close to 73 inches.

• We are confident that the mean height of all members of the high school boy's basketball team is close to 73 inches.

• We are confident that the mean height of all professional basketball players is close to 73 inches.

Historical records show that there is a strong negative correlation between global temperatures and the number of pirates on the planet. As global temperature has increased the number of pirates has decreased. A historian says that global warming caused the extinction of pirates. Is this an experiment or an observational study?

• Experiment

• Observational study

Historical records show that there is a strong negative correlation between global temperatures and the number of pirates on the planet. As global temperature has increased the number of pirates has decreased. A historian says that global warming caused the extinction of pirates. Is it reasonable to say that global warming caused the extinction of pirates?

• Yes, it is reasonable.

• No. No experiment was conducted. Correlation does not mean causation.

• Only in some cases.

• There is not enough evidence.

A random sample of high school seniors was selected and asked how much time they spend on social media each day. The average for the sample was 3.8 hours. Which of the following would be a reasonable conclusion?

• I am confident that the mean number of hours spent on social media for all high school students is 3.8 hours.

• I am confident that the mean number of hours spent on social media for all high school seniors is close to 3.8 hours.

• I am confident that the mean number of hours spent on social media for this sample of high school seniors is 3.8 hours.

• No reasonable conclusion possible.

A veterinarian wants to estimate how many hours per day that dogs sleep. To do so, she selects a random sample of 20 dogs from her clinic and asks the owners to carefully record the number of hours their dog sleeps in a given day. The mean number of hours of sleep reported by the owners is 15.5 hours.

• The veterinarian is confident that the mean number of hours that golden retrievers sleep is around 15.5 hours per day.

• The veterinarian is confident that the mean number of hours that all dogs at this clinic sleep per day is around 15.5 hours.

• The veterinarian is confident that the mean number of hours that all dogs sleep per day is around 15.5 hours.

• The veterinarian is confident that the mean number of hours that all pets sleep per day is around 15.5 hours.

Professor Yin selects a random sample of 30 students from Penn State University and asks each student whether or not they live on campus. He finds that 72% of the surveyed students live on campus. If Professor Yin were to select a different random sample of 30 students, do you think he would get the exact same result?

• Yes, because his result is based upon a random sample.

• Yes, because 30 is a large sample size.

• No, because of sampling variability.

• No, because a sample size of 30 is very small.

An administrator would like to know what proportion of students have cheated on a test or quiz. They select a random sample of 50 students and found that 4 percent admitted to cheating on a test or quiz. This result is not trustworthy. What is the most likely result of this flaw?

• A) The sample percent is likely similar to the percent of all students who have cheated on a test or quiz.

• B) The sample percent is likely greater than the percent of all students who have cheated on a test or quiz.

• C) The sample percent is likely less than the percent of all students who have cheated on a test or quiz.

• D) The sample percent is likely the same as the percent of all students who have cheated on a test or quiz.

Which of the following statement is true about the population?

• The population is always a very large group, for which every member of the population cannot be surveyed.

• The population is the group of individuals for which we collect data.

• We survey all members of the population in order to learn about the sample.

• We can learn about the population by selecting a random sample from the population and learning about the random sample.

Which of the following statements is true about the sample?

• What we learn from a random sample can be used to make an inference about the population from which the sample was selected.

• Each sample taken from a population will produce the same sample mean.

• We survey all members of the population in order to learn about the sample.

• The sample is always a very small group.