Boxplots: Data cycle, bias, sampling, and outliers

Which is the best survey question to gather data?

• What do you think about homework?

• How much time do you spend on homework daily?

• Do you do your homework regularly?

• Why do students have homework?

You want to find out the average number of hours students in your school spend doing homework each week. Which sampling method is best?

• Surveying 25 students in your homeroom class

• Surveying 100 students from one subject only

• Surveying 50 randomly selected students from all grade levels

• Surveying 200 students who are in the library after school

A teacher wants to know how often students eat breakfast. Which survey design introduces bias?

• Asking every 10th student entering the school

• Sending an email survey to all parents

• Asking only students who are in the cafeteria during breakfast

• Randomly selecting students from a list of all students

A group of students records the number of hours they spend on the phone each day: 2, 5, 7, 7, and 30. Which statement about the data is correct?

• The outlier is 30, which makes the mean larger than most of the data values.

• The outlier is 2, which makes the median smaller than the mean.

• The outlier is 30, which has no effect on the data’s range.

• There is no outlier because all values are part of the data set.

How does a random sample help reduce bias in a survey?

• It guarantees equal responses from all groups.

• It ensures each member of the population has an equal chance of being selected.

• It automatically increases the size of the population being surveyed.

• It removes the need for data organization.

A sample of 50 students is chosen to represent a school population of 800 students. What is the best way to determine if the sample is representative?

• Check if students were selected randomly from different grades and groups.

• Ensure the sample includes all students from one grade.

• Confirm the sample has the same number of boys and girls.

• Make sure the sample includes students with similar hobbies.

A data set shows the weekly screen time of students: 3, 5, 7, 7, 50 hours. What is the effect of the outlier (50 hours)?

• It decreases the median.

• It increases the mean.

• It has no effect on the mode.

• It reduces the range.

A boxplot is the best graphical representation of a data set when:

• There are multiple modes in the data set.

• The data set includes an outlier that affects the spread.

• The data is entirely categorical.

• The data set is small and contains no extreme values.

When analyzing data, how can bias affect the results of a survey?

• It ensures all data is accurate.

• It makes the sample more representative of the population.

• It can lead to misleading conclusions by over-representing certain groups.

• It eliminates the need for a random sample.

Which of the following is not a valid method for collecting data to answer a formulated question?

• Conducting a survey to ask students about their favorite hobbies

• Observing how many students use the library during lunch

• • Guessing how many hours students study based on personal experience

• Measuring the height of plants in an experiment to test fertilizer effectiveness