good morning afternoon night evening whenever you're watching this welcome back to the mr sin channel last time we went over topic 1.1 of ap psychology and today we're continuing with ap psychology as we go into unit 1 topic 2 research methods in psychology when conducting experiments psychologists are trying to investigate a hypothesis experiments are the only research method that isolates cause and effect now i mentioned that experiments are trying to investigate a hypothesis a hypothesis is a testable prediction an assumption that is made before any research has been completed oftentimes students confuse a hypothesis with a theory a theory is supported by data from research that has been completed and it explains a question or a thought now whenever we're conducting research or an experiment we need to make sure that we're aware of our own biases and how they may be impacting our observations and the experiment we'll talk more about biases in our unit 1 topic 4 video but for now one of the ways in which we can counter bias is by creating operational definitions operational definitions are statements that outline the procedures used in the study this allows others to be able to replicate the study and be able to test the results when creating operational definitions you need to define the variables and state how you intend to measure them that way others can replicate your study for example if we are measuring the impact of a new drug on the health of students we could define the drug by stating participants would take 400 milligrams per day of the drug for a year and we could measure the health of the students by looking at how many times they got sick over the course of a year now one way in which we can test our hypothesis is by using surveys these are often commonly used to collect self-reported data from individuals questions often ask for individuals opinions thoughts what they've done or may ask for factual information about an individual surveys can be excellent tools for gathering lots of data very quickly oftentimes they're used for sensitive topics where participants may feel uncomfortable answering questions without anonymity where service can get tricky though is with the wording surveys can have misleading questions that can impact how participants respond to the question this is known as the wording effect for example when surveying people about if they support the government giving aid to the less fortunate people are more receptive to aid for the needy than of welfare how we word questions impacts how the participants view the questions and also impacts the answers they give another aspect of surveys that can be tricky is how you determine who's going to answer the question oftentimes we're not surveying the entire population and that's because it's not possible to survey the population one quick note here when you hear population in a survey or study it's talking about all the individuals in the group being studied a sample is when individuals in a population are selected to represent the population in the research study researchers use sample groups to represent a population in a survey and also all the other different types of research methods when trying to select individuals from a population to create a sample group researchers can use random sampling this is when each individual in a population has an equal chance of participating researchers can also use a stratified sampling which is when they take the population dividing into different subcategories and randomly take a sample from each subcategory for example let's say i want to study the work culture at an office and i don't have time to talk to every single employee who works there that would be the population so i need to create a sample group that will represent the population now i want to make sure though that we have people from all the different departments i want someone from sales accounting the warehouse workers management and what i could do then is use a stratified sample that way i will randomly take from each of my subcategories to represent the population in my study now whenever researchers are creating a sample the goal is to create a representative sample this means that the sample group in the study represents all the different people in the population however one issue that comes up when picking a sample group is sampling bias this is when a group that is representing the population the study does not represent the entire population another research method that is used is case studies these are often used to provide an in-depth look into a specific group individual or study case studies analyze different perspectives of a topic or subject it'll provide information a chronological order it's great at showing a complete picture of something however case studies are often expensive and require a pretty considerable amount of time another weakness of case studies is that the individuals or the grouping study may act differently since they know they're being observed and they know they're part of a study this is known as the hawthorne effect and this is when subjects alter their behaviors because they're being aware they're being observed researchers could also use correlational studies to look at the relationship between two different variables and the strength of that relationship however these studies do not show cause and effect always remember correlation does not mean causation for example do i really think there's a connection between the amount of honey produced by bee colonies in the united states of america and legal execution or a connection between the per capita consumption of chicken in the united states and the total u.s crude oil imports or what about the number of people who tripped over their own two feet and died and the number of people who drowned by falling into natural water no just because we have correlations here does not mean that one variable caused the other there is always the chance that there was a third variable that was impacting the study if we do have outside variables impacting a study it's known as the third variable problem we'll talk more about correlational studies and also the third variable problem in our next topic review video research can also be done through naturalistic observation this is research that observes behaviors as they happen in a real world setting there's no lab or stage study the goal here is to observe people in their natural environments and try to gather authentic data here researchers hope to better understand who individuals really are one issue that can come up with this form of research is if someone's going to volunteer to participate in research they need to give informed consent which when they do that means they're aware that they're being observed and they may alter their behavior another issue that could come up is depending on how long the study is the researcher may not be getting the full context of the situation they also might be only getting a small glimpse for example if you were to observe my high school in 2021 you would have been given skewed data on how our school is run this is because our school made a variety of changes to the school day and to the layout of our building due to covet 19. these are not normal for our school year however for that year alone they were implemented one last thing before we go on to the next research method both case studies and naturalistic observation do not explain behavior they just describe it and that's important to remember another research method that researchers can utilize is cross-sectional studies this compares different groups for example participants of different ages being compared at the same time these studies provide a snapshot into a group and do not give researchers a complete picture or researchers may decide to use longitudinal studies which follow one particular group or individual over a long period of time one issue that can come up with these studies is the information is too specific to the group or individual beings observed and would not be able to be applied to the population plus these studies can be expensive and also very time consuming and there is the chance that participants may drop out but at the same time these studies excel at showing changes over a long period of time we often use longitudinal studies to better understand people and their development a topic we'll talk more about during unit 6. remember that each of these different types of research methods have different strengths and weaknesses and they'll be used in different situations now comes the fun part though now comes the time to practice what we've learned answer the questions on the screen and check your answers in the comments section below also if you want more topic review videos for ap psych don't forget to like the video and subscribe as always i'm mr sin and until next time i'll see you online [Music] 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