Which example is of researcher bias in interpreting data? A scientist wishes to determine the area of an ice sheet. To do so, he relies on spectrographic images sent by satellite.

A health official investigates the spread of HIV in her city. She takes a census of the HIV status of every adult resident.

A geologist wants to determine whether the water level of an aquifer is declining. To find the answer, he digs a well.

A researcher seeks to prove that babies smile at two months old. She counts some confused expressions as smiles.