To find the slope of the line, youll need to perform a regression analysis. Longitudinal studies can last anywhere from weeks to decades, although they tend to be at least a year long. 12 terms. What are some advantages and disadvantages of cluster sampling? Some examples of quantitative data are your height, your shoe size, and the length of your fingernails. These principles include voluntary participation, informed consent, anonymity, confidentiality, potential for harm, and results communication. Spontaneous questions are deceptively challenging, and its easy to accidentally ask a leading question or make a participant uncomfortable. In experimental research, random assignment is a way of placing participants from your sample into different groups using randomization. Login to buy an answer or post yours. Individual differences may be an alternative explanation for results. Its a form of academic fraud. discrete. The correlation coefficient only tells you how closely your data fit on a line, so two datasets with the same correlation coefficient can have very different slopes. Random erroris almost always present in scientific studies, even in highly controlled settings. 2. Why are reproducibility and replicability important? What are the main qualitative research approaches? Whats the difference between correlation and causation? . Its one of four types of measurement validity, which includes construct validity, face validity, and criterion validity. Peer-reviewed articles are considered a highly credible source due to this stringent process they go through before publication. A hypothesis is not just a guess it should be based on existing theories and knowledge. The American Community Surveyis an example of simple random sampling. Action research is focused on solving a problem or informing individual and community-based knowledge in a way that impacts teaching, learning, and other related processes. Removes the effects of individual differences on the outcomes, Internal validity threats reduce the likelihood of establishing a direct relationship between variables, Time-related effects, such as growth, can influence the outcomes, Carryover effects mean that the specific order of different treatments affect the outcomes. A confounding variable is a third variable that influences both the independent and dependent variables. If you fail to account for them, you might over- or underestimate the causal relationship between your independent and dependent variables, or even find a causal relationship where none exists. Its a non-experimental type of quantitative research. With this method, every member of the sample has a known or equal chance of being placed in a control group or an experimental group. The difference between explanatory and response variables is simple: In a controlled experiment, all extraneous variables are held constant so that they cant influence the results. A true experiment (a.k.a. Random assignment helps ensure that the groups are comparable. You already have a very clear understanding of your topic. Its what youre interested in measuring, and it depends on your independent variable. Quantitative data in the form of surveys, polls, and questionnaires help obtain quick and precise results. Discrete variables are those variables that assume finite and specific value. Dirty data can come from any part of the research process, including poor research design, inappropriate measurement materials, or flawed data entry. The two types of external validity are population validity (whether you can generalize to other groups of people) and ecological validity (whether you can generalize to other situations and settings). An independent variable represents the supposed cause, while the dependent variable is the supposed effect. Structured interviews are best used when: More flexible interview options include semi-structured interviews, unstructured interviews, and focus groups. Samples are used to make inferences about populations. In general, you should always use random assignment in this type of experimental design when it is ethically possible and makes sense for your study topic. What is the difference between a longitudinal study and a cross-sectional study? Categorical variables are those that provide groupings that may have no logical order, or a logical order with inconsistent differences between groups (e.g., the difference between 1st place and 2 second place in a race is not equivalent to . Discriminant validity indicates whether two tests that should, If the research focuses on a sensitive topic (e.g., extramarital affairs), Outcome variables (they represent the outcome you want to measure), Left-hand-side variables (they appear on the left-hand side of a regression equation), Predictor variables (they can be used to predict the value of a dependent variable), Right-hand-side variables (they appear on the right-hand side of a, Impossible to answer with yes or no (questions that start with why or how are often best), Unambiguous, getting straight to the point while still stimulating discussion. Purposive and convenience sampling are both sampling methods that are typically used in qualitative data collection. Next, the peer review process occurs. Above mentioned types are formally known as levels of measurement, and closely related to the way the measurements are made and the scale of each measurement. Data collection is the systematic process by which observations or measurements are gathered in research. Categorical data requires larger samples which are typically more expensive to gather. Operationalization means turning abstract conceptual ideas into measurable observations. We have a total of seven variables having names as follow :-. Blinding means hiding who is assigned to the treatment group and who is assigned to the control group in an experiment. Types of quantitative data: There are 2 general types of quantitative data: What are the two types of external validity? (A shoe size of 7.234 does not exist.) Because there are no restrictions on their choices, respondents can answer in ways that researchers may not have otherwise considered. Snowball sampling is a non-probability sampling method. A control variable is any variable thats held constant in a research study. A confounding variable is closely related to both the independent and dependent variables in a study. : Using different methodologies to approach the same topic. If you have a list of every member of the population and the ability to reach whichever members are selected, you can use simple random sampling. Question: Patrick is collecting data on shoe size. In randomization, you randomly assign the treatment (or independent variable) in your study to a sufficiently large number of subjects, which allows you to control for all potential confounding variables. However, some experiments use a within-subjects design to test treatments without a control group. How do you plot explanatory and response variables on a graph? Mixed methods research always uses triangulation. The Pearson product-moment correlation coefficient (Pearsons r) is commonly used to assess a linear relationship between two quantitative variables. Types of Statistical Data: Numerical, Categorical, and Ordinal Methodology refers to the overarching strategy and rationale of your research project. However, it provides less statistical certainty than other methods, such as simple random sampling, because it is difficult to ensure that your clusters properly represent the population as a whole. is shoe size categorical or quantitative? Random sampling or probability sampling is based on random selection. In all three types, you first divide the population into clusters, then randomly select clusters for use in your sample. Stratified sampling and quota sampling both involve dividing the population into subgroups and selecting units from each subgroup. Youll also deal with any missing values, outliers, and duplicate values. You take advantage of hierarchical groupings (e.g., from state to city to neighborhood) to create a sample thats less expensive and time-consuming to collect data from. Whats the difference between a statistic and a parameter? You should use stratified sampling when your sample can be divided into mutually exclusive and exhaustive subgroups that you believe will take on different mean values for the variable that youre studying. Data cleaning involves spotting and resolving potential data inconsistencies or errors to improve your data quality. Finally, you make general conclusions that you might incorporate into theories. Face validity and content validity are similar in that they both evaluate how suitable the content of a test is. It occurs in all types of interviews and surveys, but is most common in semi-structured interviews, unstructured interviews, and focus groups. To design a controlled experiment, you need: When designing the experiment, you decide: Experimental design is essential to the internal and external validity of your experiment. You can ask experts, such as other researchers, or laypeople, such as potential participants, to judge the face validity of tests. A semi-structured interview is a blend of structured and unstructured types of interviews. How is inductive reasoning used in research? May initially look like a qualitative ordinal variable (e.g. categorical data (non numeric) Quantitative data can further be described by distinguishing between. Can I include more than one independent or dependent variable in a study? This value has a tendency to fluctuate over time. Military rank; Number of children in a family; Jersey numbers for a football team; Shoe size; Answers: N,R,I,O and O,R,N,I . A regression analysis that supports your expectations strengthens your claim of construct validity. In multistage sampling, you can use probability or non-probability sampling methods. 1.1.1 - Categorical & Quantitative Variables How do you use deductive reasoning in research? You can't really perform basic math on categor. In a factorial design, multiple independent variables are tested. The external validity of a study is the extent to which you can generalize your findings to different groups of people, situations, and measures. Inductive reasoning is a method of drawing conclusions by going from the specific to the general. In scientific research, concepts are the abstract ideas or phenomena that are being studied (e.g., educational achievement). This includes rankings (e.g. Patrick is collecting data on shoe size. Thus, the value will vary over a given period of . Categorical variable. So it is a continuous variable. Longitudinal studies and cross-sectional studies are two different types of research design. Whats the difference between quantitative and qualitative methods? Random error is a chance difference between the observed and true values of something (e.g., a researcher misreading a weighing scale records an incorrect measurement).