Question 1

_____ occurs when participants decide if they wish to be studied in the experimental or control group.

Accepted Answer

Self-selection occurs when participants choose whether they want to be in the experimental or control group based on personal factors or preferences. This can lead to biased results as individuals who opt to participate in the study may have different characteristics than those who choose not to participate or who are randomly assigned to a group. Random assignment, on the other hand, involves randomly assigning participants to the experimental or control group to ensure that they are comparable at the outset of the study. Informed consent refers to the process of obtaining participants' voluntary agreement to participate in the study after they have been provided with information about the study, including its purpose, procedures, potential risks and benefits, and confidentiality. Random sampling is a method of selecting a representative sample from a larger population using a probability-based sampling technique.

Question 2

What is the major problem associated with self-selection as a way to assign participants to the experimental and control groups?

Accepted Answer

Self-selection means that participants choose which group they will be in, which means that the two groups may differ in many ways other than the variable being studied. This can make it difficult to determine whether any differences between the groups are due to the treatment or other factors.

Question 3

Diana wants to see if heat causes happiness. She asks 100 participants to come to the laboratory, and as they walk in, she asks each person to choose a warm booth or a cool booth. On the basis of their choices, participants spend 20 minutes in one or the other booth before rating their levels of general happiness. What's wrong with Diana's experiment?

Accepted Answer

Diana didn't randomly assign participants to the warm or cool booths, which introduces the possibility of participant bias influencing the results. Additionally, there is no control group in this experiment since all participants are exposed to either warm or cool conditions, which makes it difficult to draw conclusions about the effect of heat on happiness.

Question 4

In an experiment, researchers exposed half the children to 2 hours of violence on television every day for a month and made sure the other half saw no violence on television at all. At the end of the month, they measured the level of aggressiveness in the children. What were the children who were exposed to violent television?

Accepted Answer

The children who were exposed to violent television are the experimental group because they were the ones being manipulated or exposed to the independent variable (violence on television).

Question 5

Researchers wanted to see if listening to calm music would reduce heart rates. Half of the research participants sat quietly and listened to calm music, and the other half sat quietly and listened to no music at all. The group that listened to the music is called the:

Accepted Answer

The group that listened to the music is the experimental group because they are the ones being exposed to the independent variable (calm music) and are being compared to the control group (those who listened to no music). The independent variable is the music and the dependent variable would be the heart rates, which are measured and compared between the two groups.

Question 6

In an experiment, researchers exposed half the children to 2 hours of violence on television every day for a month and made sure the other half saw no violence on television at all. At the end of the month, they measured the level of aggressiveness in the children. What were the children who weren't exposed to any violence on television?

Accepted Answer

The children who were not exposed to any violence on television are part of the control group, which is the group that does not receive the treatment or exposure to the independent variable (in this case, violence on television).

Question 7

_____ occurs when participants are assigned to the experimental or control group by coin flip.

Accepted Answer

Random assignment is the process of assigning participants to different groups in an experiment through a chance mechanism such as a coin flip. This helps to minimize bias and ensure that each group has an equal chance of experiencing the independent variable being tested. Self-selection refers to participants choosing their own group, double-blind experimentation involves neither the researcher nor the participants knowing which group they are in, and random sampling is the process of selecting participants at random from a larger population.

Question 8

Descriptive statistics include measures such as mean or standard deviation. What is another group of statistics that is used to determine what kind of conclusions can be drawn from the results of an experiment?

Accepted Answer

Inferential statistics are used to draw conclusions and make inferences about a larger population based on data collected from a sample. These statistics include hypothesis testing, confidence intervals, and regression analysis.

Question 9

A result is said to be statistically significant if the odds that random assignment has failed in an experiment is less than _____ percent.

Accepted Answer

Conventionally, a significance level of 0.05 (5%) is commonly used in hypothesis testing to determine if a result is statistically significant. Hence, the answer is B, as if the p-value is less than 0.05, it suggests that the result is statistically significant.

Question 10

Researchers wanted to see if adults were actually afraid of the dark by exposing them to different levels of light in a room while measuring their heart rates. In this experiment, what are the different levels of light?

Accepted Answer

The different levels of light are the independent variable. The dependent variable is the participants' heart rates, which will be measured based on the level of light they are exposed to. There is no control group or experimental group mentioned in this scenario.

Question 11

Researchers wanted to see if listening to calm music would reduce heart rates. Half of the research participants sat quietly and listened to calm music, and the other half sat quietly and listened to no music at all. The group that did not listen to the music is called the:

Accepted Answer

The control group is the group that does not receive the experimental treatment, in this case, listening to calm music. The purpose of the control group is to provide a baseline comparison for the experimental group, which is the group that does receive the experimental treatment. Therefore, the best choice is C, which represents the control group.

Question 12

When the odds are acceptably low that random assignment hasn't failed in an experiment, the results of the experiment are said to be:

Accepted Answer

When the odds are acceptably low that random assignment hasn't failed, it means that the results of the experiment are statistically significant, indicating that the observed effects are likely not due to chance and can be attributed to the treatments being tested.

Question 13

A researcher wants to assess the effects of varying amounts of alcohol on ratings of perception of friendliness. Three groups of people are given either 1, 2, or 3 beers to drink. Three more groups of people are given either 1, 2, or 3 non-alcoholic beers to drink. Then, all participants are shown a series of pictures of people's faces and are asked to rank the perceived friendliness of each face on a scale from 1 to 10. Each face was presented for 5 seconds. In this experiment, the dependent variable is:

Accepted Answer

The dependent variable in this experiment is the ratings of perceived friendliness, as this is what is being measured and compared across the different groups. The independent variables are the amount of alcohol in the beer and whether or not the beer is alcoholic. The length of time each face is presented is a controlled variable to ensure consistency across participants, but it is not the focus of the study. The number of groups is also not the dependent variable, as it is simply a feature of the study design.

Question 14

Which method does NOT use random assignment to assign participants to groups?

Accepted Answer

Random assignment is crucial in order for groups to be equivalent at the start of the experiment. If group assignment is based on the order that participants arrive, there may be systematic differences between groups that could confound the results. A, B, and C all use random assignment methods to ensure equal group allocation.

Question 15

When random assignment fails to create equivalent groups, the problem of _____ occurs.

Accepted Answer

When random assignment fails to create equivalent groups, the problem of third variables occurs. Third variables are extraneous factors that can affect the outcome of a study, leading to differences between groups that were not caused by the independent variable of interest. This can compromise the internal validity of a study. Sampling error is a different problem that can occur when a sample is not representative of the population, self-selection refers to bias introduced when individuals choose to be part of a study, and external validity relates to the generalizability of study findings to other populations or settings.

Question 16

Researchers wanted to see if adults were actually afraid of the dark by exposing them to different levels of light in a room while measuring their heart rates. In this experiment, what are the heart rates of the participants?

Accepted Answer

The heart rates of the participants are the dependent variable, as they are being measured in response to the independent variable (different levels of light in the room). The independent variable is the level of light, as it is being manipulated by the researchers. A control group may or may not be used in this experiment, but it would be a group that is not exposed to any changes in light levels, while an experimental group would be exposed to different levels of light.

Question 17

Wally wants to see if room temperature affects happiness. He invites participants to the laboratory, where half are seated for 20 minutes in a booth held at a constant 68 degrees, and the other half are seated in an identical booth for 20 minutes at a constant 88 degrees. Wally then asks members of each group to rate their level of happiness. What is the dependent variable in this experiment?

Accepted Answer

The dependent variable in this experiment is the rating of happiness, as it is what is being measured and expected to change based on the different room temperatures. The other variables listed are independent variables or control variables.

Question 18

Random assignment to groups helps ensure that:

Accepted Answer

Random assignment to groups helps ensure that groups do not differ on variables not of interest, which increases the internal validity of the experiment. A, B, and D are not necessarily ensured by random assignment alone.

Question 19

When one manipulates an independent variable, at least how many groups are created?

Accepted Answer

When one manipulates an independent variable, at least two groups are created: the experimental group and the control group. The experimental group is the group that receives the manipulated variable, while the control group does not. Comparing the results of these two groups allows researchers to draw conclusions about the effects of the independent variable.

Question 20

A researcher wants to assess the effects of varying amounts of alcohol on ratings of perception of friendliness. Three groups of people are given either 1, 2, or 3 beers to drink. Three more groups of people are given either 1, 2, or 3 non-alcoholic beers to drink. Then, all participants are shown a series of pictures of people's faces and are asked to rank the perceived friendliness of each face on a scale from 1 to 10. In this experiment, the independent variable is:

Accepted Answer

The independent variable is the amount of alcohol consumed. This is the variable that is being manipulated by the researcher, and is expected to have an effect on the ratings of perceived friendliness. The other variables, such as the number of groups or the pictures of faces, are either controlled or measured in the experiment, but are not being systematically varied.

Quiz 2: Section 2: Methods in Psychology