Topic 6 Test

What is a valid inference? Use the drop-down menus to explain your answer.

A valid inference is one that is true about the ​ (a)   based on a ​ (b)   .

• population
• example
• data
• sample
• representative sample
• single example
• data point

Maria records random speeds from three different Internet providers in the table. Which company offers the fastest mean downloading speed?

• CityNet

• Able Cable

• Tel-N-Net

• Impossible to determine from the information given.

Lucy collects data from a random sample of seventh-graders. Out of 40 respondents, 7 attended after-school programs. Of the 200 seventh-graders attending Lucy's school, how many would be expected to attend afterschool programs?

Tricia surveys students in her computer class about time spent on computers by students in her school. Is this a representative sample? Explain.

• No; only a few students in the school take computer class.

• No; students in computer class likely use computers more than other students.

• Yes; students in computer class are representative of the school.

• Yes; students in computer class are representative of people in the town.

Caleb is comparing the growth of plants using two different fertilizers. Use the box plots to make an inference using the variability of the data. Drag words to complete the statement. Words may be used once, more than once, or not at all.

The range and IQR are ​ (a)   in Group B as compared to Group A, so there is ​ (b)   variability in the growth of plants in Group B.

• greater
• less

A school principal wants to know what theme students prefer for the spring dance. There are 150 students in the 6th grade, 200 students in the 7th grade, and 187 students in the 8th grade. Select the two representative samples that can help the principal draw conclusions about which themes the students prefer.

• The students in the 7th grade homerooms.

• The same number of students from each grade whose names are randomly selected from a hat.

• The members of the student council.

• Students who attended the winter dance.

• 50 sixth graders, 67 seventh graders, and 62 eighth graders

Annabel is comparing the distances that two electric cars can travel after the battery is fully charged. Use the measures of center to make an inference about the data. Use the drop-down menus to complete your answer.

​ (a)   can travel further than ​ (b)   after the battery is fully charged.

• Car B
• Car A

Annabel is comparing the distances that two electric cars can travel after the battery is fully charged. Based on the data, which car performs most consistently? Explain.

• Car A because the measures of center are smaller for Car A than for Car B.

• Car B because the measures of center are smaller for Car B than for Car A.

• Car A because the measures of variability are smaller for Car A than for Car B.

• Car B because the measures of variability are smaller for Car B than for Car A.

Which of the following survey methods is least likely to result in statistical bias?

• Ask every 3rd person you see at the school gym if they like to work out.

• Ask all the 6th graders what afterschool activity is most popular.

• Ask a random sample of your friends which candidate they support for school president.

• Ask a random sample of all students what they would like the school mascot to be.

Sari wants to start an afterschool business in her neighborhood. She decides to ask her neighbors what services they need. She asks all the neighbors who have dogs if they would prefer a dog-walking service or a lawn-mowing service. Select the two reasons Sari's method of collecting data may generate results with statistical bias.

• She only asks neighbors with dogs.

• She asks people in her neighborhood.

• She asks everyone the same question.

• She only asks about two specific services.

• She writes down everyone's answer.