Unit Test Answers

What proportion of families own as opposed to rent their home? To find out, an urban planner selected a random sample of 400 families in a large city to participate in a survey about homeownership. Of the 362 families that responded to the survey, 42% reported that they own their home. Which of the following statements about the survey results is true?

An urban planner examines police-report data for many cities and towns and discovers that cities with professional football teams tend to have higher numbers of reported small crimes, such as burglary.

A trade school would like to measure the long-term success of its graduates after they leave the school, and emails a survey requesting information from graduates about their work experience. One question asks graduates if they are currently employed in the field they studied in school, while another asks them to share their annual salary. What type of bias is most likely to be present in the survey results?

A trade school would like to measure the long-term success of their graduates after they leave the school. The school emails a survey requesting information from graduates about their work experience. One question asks graduates to share their annual salary, and the results of the question will be shared in a brochure for incoming students. Is it likely that the survey results will provide an accurate estimate of mean annual salary for all of the school’s graduates?

Many movie theaters show advertisements before feature films to increase concession sales. However, many customers complain about the length the advertisements add to their time at the theater. To understand the effect of advertising, a movie theater manager chooses random days during the month when the concession advertisements are not shown. On the remaining days, the concession advertisements are shown as usual. The manager then records the concession sales for each day.

Miranda is conducting a poll to determine how many students would attend a students-only school dance if one was held. Which sample is most likely to yield a representative sample for the poll?

An article in a psychology journal claims that young students who play a musical instrument tend to have higher test scores on state math exams. To assess the claim, a government official considers two methods to collect data.Method 1: Contact many city schools and ask them to provide summary data on state math exam performance and students who participate in music lessons.Method 2: Choose two city schools and provide free music lessons to students who register. At the end of the year, compare state math exam scores for students who participated in the music lessons with the scores for those who did not.

Sam kept track of the number of problems he was assigned for his math homework on the box plot.Which statement must be true according to the box plot?

A farmer sows 100 seeds of a new type of corn and wants to quickly determine the yield, or total number of ears of corn, for the crop when it has matured. He decides to take a simple random sample of the crop by using a random digit table. What is the fewest number of digits that should be used, given that there are 100 plants in total?

The president of the math club is conducting a survey to see where the twelfth-grade class wants to go on their field trip. Instead of asking the whole class, she surveys only the twelfth-grade members of the math club. She records their choices and plans to present the results to the school principal. What type of sampling did she use?

Many large cities have considered or passed proposals that ban the use of plastic grocery bags in stores. A concerned student would like to measure if residents of her hometown would consider a similar ban on plastic bags. Standing in a busy shopping area, the student approaches adults and asks, "Items made of plastics are a dangerous, growing source of pollution to our world’s oceans and threaten many animal species. Given this, would you support a ban on plastic shopping bags in our city stores?” Which type of bias is most likely to be present in the survey results?

Steve determined the number of states each of his friends has visited.Which statement must be true according to the box plot?

A biologist wonders if the life span of bats will be affected by two new food sources from invasive species moving into an area. To conduct the experiment, the biologist needs three treatment groups: a group where the diet will not include invasive species (control), a group where the diet will include one invasive species (treatment group 1), and another group where the diet will include the other invasive species (treatment group 2). The biologist chooses the first cloud-free night and catches the first 18 bats that fly out of a cave. The first six bats will be the control group, the second six will be treatment group 1, and the last six will be treatment group 2.

A researcher is comparing the effectiveness of three devices designed to help people who snore. There are 60 people who snore participating in the experiment who are labeled 01–60. Using a table of random digits, the researcher will randomly place the participants into three equally sized treatment groups suitable for comparison. Carry out the random assignment using the given selection from a table of random digits, starting with the first row and first column.

Marisa recorded the number of hours she babysat each day last summer. She plotted the data in the box plot.