Unit Test Answers

A nutritionist would like to estimate the number of times adults exercise each week. To collect information, the nutritionist emails the members of the local fitness center. Which of the following describes the bias that may arise from the results?

A community is considering raising funds to pay for improvements to the community swimming pool. To measure the level of interest, community leaders went door-to-door in a few neighborhoods and interviewed residents. Of the 230 residents contacted, 157 support raising funds to pay for improvements. Which of the following represents the sample in this setting?

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?

If , then what is –K?

What are the values of x and y in the matrix equation below?

Researchers would like to assess the overall health of white pine trees in a state park. Using a computer program, the researchers selected 100 random points in the state park and assessed the trees closest to the selected points. Of the 100 trees selected, 24 showed damage to their lower limbs. Which of the following describes the population in this setting?

Which would be the next step in solving for matrix A?

Matrix P is shown below. Given that Matrix P equals Matrix Q, what is the value of

Opal is collecting data on water levels in different parts of town. She notices that her sample data has a low-value outlier. Which statement must be true?

Ines created a coefficient matrix to represent the system of linear equations below.Which type of matrix did Ines create?

A student would like to estimate the average number of text messages sent by cell-phone users in a day. Which of the following methods would provide a voluntary response sample?

The grades of a science test are normally distributed. Thanh finds that his grade on the test has a z-score of –2.5. Which statement must be true?

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?

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?

Which property is shown in the matrix addition below?

Which set of population data is the least dispersed from its mean?

The set of life spans of an appliance is normally distributed with a mean = 48 months and a standard deviation = 8 months. What is the life span of an appliance that has a z-score of –3?

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?

The vertices of a rectangle are given in the columns of the matrix . If is found to perform a transformation, what are the coordinates of the transformed rectangle?

The times taken to assemble a clock at a factory are approximately normally distributed with a given mean = 3 hr and standard deviation = 0.5 hr. What percentage of the times are between 2 hr and 4 hr?

A supervisor finds the mean number of miles that the employees in a department live from work. He finds and . Which statement must be true?

The times of all 15 year olds who run a certain race are approximately normally distributed with a given mean = 18 sec and standard deviation = 1.2 sec. What percentage of the runners have times less than 14.4 sec?