Question

Eduardo's mother just bought a new vacuum cleaner that she loves. Eduardo wants to know if it really cleans better than the old one. He gets a few identical carpet samples and works an equal amount of sand and dirt into each one.

Then he gets a panel of ten people to rate how well each vacuum cleans.

Which of the following experimental setups will be the most objective and have the least bias?

A. Eduardo leaves 1/3 of the samples dirty. He divides the other samples into two groups. He cleans each group with a different vacuum. He puts the samples in a random order, then asks the panelists to rate how clean each sample is.

B. The panelists watch Eduardo use each vacuum to clean a carpet sample, then they rate how clean each sample is.

C. Each panelist cleans one carpet sample with each vacuum, then rates how clean each sample is.

D. Eduardo leaves 1/3 of the samples dirty. He divides the other samples into two groups. He cleans each group with a different vacuum, then he asks the panelists to rate how clean each group is.

Answer 1

it is a

Step-by-step explanation:

Eduardo leaves 1/3 of the samples dirty. He divides the other samples into two groups. He cleans each group with a different vacuum. He puts the samples in a random order, then asks the panelists to rate how clean each sample is.

i just got it