In order to determine the effect companion animals might have on the moods of elderly people living alone experimenters created six groups from a large population of single people over 70 years old. They had three groups: those without pets, those who owned a dog, and those who owned a cat. They randomly selected 50 men from each of those groups and 50 women from each of those groups for a total of 300 participants. Which of the following statements about this study is correct? This study is an experiment, since it was based on a random sample. This study is an experiment, since each subject was classified into one of the six possible combinations of pet ownership and gender. This study is a combination of both an experiment and an observational study. This study is an observational study, since researchers did not assign the subjects to a gender or pet ownership status.

A second group of researchers find 400 participants who are screened for things like lifestyle preferences. They use a computer program to assign 100 participants to each of the 3 treatment groups and 100 participants to the control group. These participants will receive free groceries for life in exchange for their participation. Researchers follow up with participants once every 10 years to collect data on their health for the rest of their life.This can be considered an experiment because the researchers used:Hint, displayed belowRandom AssignmentLurking VariablesSample SurveyExperimental Design

Participants who experience anxiety are placed into two groups for a research experiment. They are separated into groups based on age. Those who are 30 and over go into one group and those under 30 into another. What type of design would this be considered? Group of answer choicesMatched design Quasi-experimental design Masked design Mixed design

Researchers ran three clinical trials, each using a different one of the following populations:250 nonsmoking men ages 18 to 25500 smoking and nonsmoking men and women ages 20 to 55300 smoking women ages 45 to 60Would you expect the results of these three experiments to be the same?

Subjects in an experiment who are exposed to an independent variable are known as what type of group?Multiple choice question.analyticalexperimentalcontrolhypothetical

Subjects in an experiment who are not exposed to an independent variable are known as what type of group?Multiple choice question.controlanalyticalexperimentalhypothetical