研究方法一：练习题

A researcher investigates the effect of a new teaching method on reading scores. They use a group of 20 students, pairing them based on their initial reading ability and then assigning one member of each pair to either the new method or the standard method. Which experimental design is being used in this study?

A psychologist is conducting an observational study of playground behavior. To ensure the reliability of their data, they use two independent observers to record the frequency of aggressive acts using a pre-defined set of behavioral categories. After the session, they compare the observers' tallies and find a correlation of \( +0.92 \). What is the primary purpose of this procedure?

In an experiment investigating the effect of noise on concentration, a researcher tests the same group of participants in a quiet room at 9:00 AM and then in a noisy room at 3:00 PM. Which extraneous variable is most likely to confound the results in this repeated measures design?

In a study measuring the reaction times (in milliseconds) of participants after consuming caffeine, a researcher calculates the following measures of central tendency and dispersion. If the data set is positively skewed, which of the following relationships between the mean, median, and mode would most likely be observed?

A researcher is studying the relationship between the number of hours spent sleeping and performance on a memory test. The resulting scattergram shows that as sleep hours increase, the number of words recalled also increases. However, the data points are widely spread from the line of best fit. Which of the following correlation coefficients most likely represents this relationship?

Explain how counterbalancing is used to deal with order effects in a repeated measures design.

In a study where the data set for memory recall scores is found to be negatively skewed, identify the relative mathematical order of the mean, median, and mode, and explain why the mean is typically the lowest value in this specific distribution.

Explain the purpose of a pilot study in psychological research and provide one reason why a researcher might choose to conduct one before a full-scale investigation.

A researcher conducted an experiment to investigate whether the presence of a mirror in a room affects the amount of time people spend grooming themselves. A group of 20 participants were randomly split into two groups. Group A was placed in a waiting room with a large mirror on the wall, while Group B was placed in an identical room without a mirror. The researcher observed the participants through a one-way mirror for 10 minutes and recorded the total duration (in seconds) each participant spent adjusting their hair or clothes.

a) Identify the independent variable (IV) and the dependent variable (DV) in this study. (2 marks)

b) Identify the experimental design used in this study and explain one strength of using this design in this context. (2 marks)

c) The researcher decides to use a covert observation. Explain one ethical issue that might arise from using a covert observation in this study and how the researcher could deal with it. (2 marks)

d) Explain why the researcher might choose to use the median rather than the mean to represent the central tendency of the grooming times if the data is found to be positively skewed. (2 marks)