Psych Res Meth Test 2 (SQ's)
CH 5 - 9 Discuss how bias in sampling affects the internal validity of your study. How is this different compared to its effects on external validity?
Internal Validity - Bias in sampling can compromise the internal validity of a study by introducing systematic errors or distortions in the relationships observed between variables. Suppose the sample does not represent the population from which it is drawn. In that case, the study may suffer from selection bias, which occurs when certain groups are overrepresented or underrepresented in the sample. External Validity—If the sample is not representative of the broader population, the study's findings may not be applicable or relevant to other populations or settings, limiting the research's external validity.
CH 6 - 1 Discuss the relation between measurement scales and interpretability of data
Interval scales usually interpret data based on a certain degree of something based on how a participant responds for instance, asking how much someone agrees or disagrees with something with no 0 point. Ordinal scales can ask the same thing, only with ranks ranging from not at all, to a certain degree. Nominal scales that only has one interpretation of something such as race, religion, etc, will be used to interpret things categorically, based on percentages or degree of something in a certain category. Ratio scales, being able to obtain things like weight, income, and age with a true 0 point can be interpreted to show how objectively true data correlates with something.
CH 5 - 1 When is a descriptive study considered appropriate, and what are the key characteristics that make it a suitable research approach in certain situations?
It's considered appropriate when a study observes common trends such as behavior, determine if trends fit a theory, examine differences in behavior of target populations, and compliment other designs. The key characteristics that make it suitable in certain situations are: -examines the who, what, when, where, and how, but it does not examine relationships among them -Doesn't manipulate variables -Focuses on external validity in that the results generalize to other samples, settings, and methods.
CH 5 - 6 Describe nonprobability sampling and apply four different methods to obtain a nonprobability sample.
Does not use a random sample, and the odds of selecting a particular individual are unknown. Convenience sampling pros - good for limited resources, less time consuming, sample is extremely accessible con - overly convenient samples may not be representative, potential selection bias Quota Sampling Pro - subgroups are identified to be included, control composition of convenience sampling Con - Potential for selection bias if participants are selected solely to meet quota, or quota isnt properly set Snow ball sampling Pros - having participants bringing more participants is less work, and can reach hard-to-reach people Cons - prone to bias due to participants not getting representative participants (e.g. participant is similar to them) Max variation sampling Pros- seeks out extremes in population, extremes may clearly define multiple perspectives Cons - prone to sampling bias, subjectivity, limited generalizability to general population
CH 6 - 3 As a researcher, discuss two ways that you would minimize the likelihood of outliers affecting your statistical results.
1. Clearly state and identify outliers, and why they might have come about, and explain how relevant they are to the average 2. Implementing proper statistical methods can also decrease the amount of outliers that portray causation innacurately
CH 5 - 3 Recognizing the importance of defining a population and sampling from it, explain how the choice of population and sampling technique can influence the generalizability of study results. Provide examples of situations where improper population definition or sampling could lead to biased conclusions.
Defining the population is important because it should clearly identify the group a researcher wants to examine. This allows the researcher to stay within the population boundaries they set to increase validity. However, sampling from the defined population must be approached properly to avoid bias and error. An accessible population, or a realistic population of people a researcher can involve in a study, may or may not have limited results in retrospect to the general population. The researcher can avoid error and bias by determining how representative this sample is to the general population. There should be specifications of how meaningful their results are based on the population they studied. Furthermore, the researcher should avoid selection bias, especially when they may select individuals more suited to proving their hypothesis. For example, a study examining the effect of sleep amount on students' grades should clearly define the population to something realistic but representative enough to work around potential confounds such as major, age, gender, GPA, etc. The accessibility of the population should ideally allow the researcher to select a larger, more diverse population to increase validity. If the researcher picks students who are more likely to receive worse grades regardless of how much they sleep, the results will be invalid
CH 5 - 14 Identify a research question that would assume the use of maximum variation sampling.
Happiness of homeless people versus upper class people. In terms of socioeconomic status, the sample takes the highest and the lowest, with nothing in between.
CH 5 - 10d Identify whether the example is Probability or Nonprobability sampling. Then describe the method of sampling being used (ex. Convenience sampling, simple random, etc.) and explain why Mei-Lynn was interested in doing a research project on 20th-century fashion. She proposed that there was some sort of relation between political policy and fashioned design during the 1900s. However, not all libraries have fully accessible archives to the public, so she selected a library with an easily and fully accessible archive with fashion magazines dating back to the 1900s. However, this library had a limited number of magazines within their collection. She used every magazine that she had access to in the archives. With the magazines and documentation of policy throughout the era, she did a comparative analysis between women's fashion trends and policy.
Non probability and convenience sampling The lack of archives led to the selection of only one libary for convenience. This library also had a limited number of magazines, making her data limited in terms of validity
CH 5 - 11 Terry is an alien who recently landed on Earth. As he started to discover the world and all its features, there was one thing he was quite interested in: ice cream. However, Terry wasn't sure what his favorite ice cream flavor was, so he wanted to conduct an experiment. He wanted to know what the best flavors of ice cream were on planet Earth. He found a Dairy Queen right down the street from his ship and tasted all the flavors that were available. He decided that Mint Chocolate Chip was the best tasting Ice Cream that Earth had to offer. Identify the population and sample Terry's study. (For extra preparation, how externally valid do you think Terry's study is?)
Population - all flavors on earth. limited external validity because flavors were only limited to dairy queen Sample: Terry's sample would be the ice cream flavors available at the Dairy Queen down the street from his ship. External validity limitations - limited to his taste only, only one place
CH 5 - 4 Describe probability sampling and apply three different methods to obtain a probability sample in various research scenarios.
Probability sampling is random, where the exact size of the population is known, and each individual has a certain chance of being selected. One method to obtain a probability sample is simple random sampling, where participants are selected from a list of the total population. Random selection may be better when the whole population can't be selected, requiring a representative enough sample in regards to the whole population. Researchers must be careful to choose based on individual characteristics, but membership of the specific population, in order to maximize its representativeness. Stratified sampling can also be used, which divides the population into subgroups, and equal numbers of each subgroup are selected.
CH 5 - 8 Discuss two advantages and two disadvantages to using convenience sampling
Pros - Easy and inexpensive to implement, often requiring minimal time and resources. -Useful for exploratory research or when access to the population is limited. Cons - Prone to selection bias, as participants are typically chosen based on convenience or accessibility rather than representativeness. -Results may not be generalizable to the broader population, as the sample may not accurately reflect population characteristics.
CH 5 - 5 Discuss the advantages and disadvantages of each method of probability sampling and highlight when each is most appropriate
Simple random sampling pro - every member of population has equal chance of selection, straightforward con - may ignore small subgroups in whole population Stratified sampling pro - representation from different subgroups may allow for more accurate representations con - may be more complex and time consuming, and requires prior definition of strata which could be innacurate Cluster sampling pro - more practical approach to sampling large populations by selecting groups rather than individuals. con - Inherent homogeneity within clusters may lead to less variability between clusters Systematic pro -
CH 5 - 2 Evaluate the validity of descriptive research by discussing the potential limitations and sources of bias that may impact the accuracy and reliability of findings. Provide an example to illustrate your points.
The limitations include the biases and measurement errors that come with it. For example, if a researcher conducts a survey about smartphone usage but only interviews people from a specific age group or socioeconomic background, the findings may not be generalizable to the broader population.
CH 5 - 15 Discuss the relationship between sampling and recruitment.
The validity of the recruitment process effects how accurate the sample is. Biased recruitment procedures may result in reduced generalizability, while unbiased, well-planned recruitment may have samples with high generalizability
CH 6 - 4 Why are descriptive statistics important in understanding your data. When would you use each and why?
They provide a visual depiction of patterns, distributions and characterisitcs of a data set. Mean - average value is important to understand for things such as test scores Mean - when data are skewed, find central tendancy. for example household income might have outliers that significantly affect the mean Mode - most frequently occuring value. might use the mode to identify the most popular color among a group of respondents Range - Use the range when you want to understand the extent of variability or dispersion in the dataset. might use the range to determine the spread of test scores within a class Standard deviation - Use the standard deviation when you want to quantify the spread or variability of the data around the mean. For example, you might use the standard deviation to assess the variability in test scores within a group of students
CH 5 - 10b Identify whether the example is Probability or Nonprobability sampling. Then describe the method of sampling being used (ex. Convenience sampling, simple random, etc.) and explain why Samari wanted to research how mental health stigma impacts beliefs towards people who are taking psychiatric medication. She created a questionnaire with multiple different scales looking at stigmatic beliefs towards mental health and psychiatric medication. To obtain her sample, she asked a small group of her friends to take the survey and share it with all of their friends. From there, Samari's friends asked their friends to share the survey with the people they know, so on and so forth.
This is nonprobability probability and Snowball sampling. It is snowball sampling because Samari picked an initial convienient sample of her friends, and asked them to get volunteers, and have those volunteers share the survey even further, which she planned to cycle. The goal here was to exponentially increase the amount of participants through referral, like that off a snowball rolling down a hill and increasing in mass.
CH 5 - 10c Luis conducts a study on how socioeconomic status is related to the number of hours worked per week in Maryland. Luis found a study describing the average yearly income of all neighborhoods in Maryland. With this information, he randomly selected 15 low-income neighborhoods and 15 high-income neighborhoods. With the neighborhoods, he sent out a survey for the participants' demographics (including yearly income, number of jobs currently, typical income usage like rent, food, etc.). Then the survey asked how many hours they clocked in (and put in outside of work) per week for past 6 months. Every single person currently employed in all neighborhoods selected responded to the survey. With these results, Luis found that lower-income Maryland residents often worked more jobs with more hours clocked in per week. Higher-income residents often put in more work outside of the "clocked-in" hours than their cohor
This is probability sampling and cluster sampling. It is cluster sampling because each neighborhood was considered a cluster within the general population of maryland, and selected at random throughout the state.
CH 5 - 10a Identify whether the example is Probability or Nonprobability sampling. Then describe the method of sampling being used (ex. Convenience sampling, simple random, etc.) and explain why Mr. Smith is a biology teacher in his local high school. He was interested in conducting a study on student preference for school subjects. He decided that he wanted a diverse sample of students involved in his study. He got a list of all the names of the students (n=400) and what grade level they were in (i.e., freshman, sophomore, junior, senior). From these 4 groups, he randomly selected 20 students from each grade level to participate in his study.
This is probability sampling and stratified sampling. It is stratified sampling because he used a diverse sample by defining 4 clearly different grades. Because he randomly selected 20 students from each grade, each student from each group had an equal chance of being selected, it was completely random at this point.
CH 6 - 2 Describe how we use standard deviation. Why is it important in terms of how we interpret our findings.
calculated by the average distance between the scores and the mean or average. This shows the amount of variation in data points Measure of variability, depending on the context of the study, can be used to interpret how accurate the study is, identify outliers, portray trends, and interpret how accurate the study was based on the measure
CH 5 - 13 What is the importance of random sampling? Why might someone choose a different sampling method than random sampling?
ensure that every member of the population has an equal chance of being included in the sample. -minimize bias, and increase generalizability to general pop Why one might not choose random samling method: -pracicality/limited resources -specific objectives
CH 5 - 7 Discuss the strengths and weaknesses of each method and provide examples of situations where nonprobability sampling may be preferred over probability sampling.
exploratory research, hard-to-reach populations, specialized populations, qualitative research. For example, maybe you have difficulty finding homeless people to conduct a study on, so you use non-probability
CH 5 - 12 Give an example of a descriptive study and explain why it is considered descriptive.
researchers distribute a questionnaire to a sample of college students, asking them about their dietary preferences, frequency of meals, types of food consumed, eating patterns, and any related behaviors. This study is considered descriptive because its primary goal is to describe and characterize the eating habits of college students - no casual relationships
