Research - The Basics
The presumed "cause", or what happens first.
What is the independent variable?
This type of data collection is good for collecting data from a large number of respondents. They can be administered online, in person, and over the phone. They are useful for gathering numerical data that can be statistically analyzed.
What is a survey or questionnaire?
Note: They are particularly good for gathering information on attitudes, behaviors, preferences, or characteristics of a large population. For example: social research to study cultural trends, public opinions, and social norms; or for educataion to assess educational outcomes, student satisfaction, teaching methods efficacy, and the impact of educational interventions.
This type of visualization is typically used for nominal data, as it displays categorical data well.
What is a bar graph?
This measure is known as the "democracy" of measures of central tendency, because all scores contribute equally.
It is calculated by summing all the values and dividing by the number of values.
What is the mean?
Discuss the pros and cons of using the mean.
The presumed "effect" or outcome; i.e., what happens last.
What is the dependent variable?
This type of data is:
1) on a continuum
2) in ranked order
3) has equal distances between ranks
What is interval data?
This type of visualization, similar to a bar graph, is more often used to represent interval and ratio data.
What is a histogram?
The height of each bar reflects the number of data points that fall into each interval, making histograms useful for understanding the shape, spread, and central tendency of a data set. Histograms are particularly helpful for highlighting the mode, detecting skewness, and identifying outliers in data.
This measure is the "mediator" of measures of central tendency, because extreme scores do not sway it.
It is the middle value in a set when the values are arranged in ascending or descending order.
What is the median?
Discuss the pros and cons of using the median.
A well-formulated one of these should 1) state a relationship between two or more variables; 2) be stated clearly and without ambiguity; and 3) be testable, meaning it should be possible to support or refute it through observation, measurement, or experimentation.
What is a hypothesis?
Talk through some examples of good research questions.
This type of data is
1) categorical
2) exclusive and exhaustive
3) not in any particular order
What is nominal data?
This term describes when a distribution has a "tail" to the left, and the "hump" to the right, meaning more of the cases fall on the right side of the graph.
What is negative skew?
Note - in this type of distribution, the mean is lower than the median.
This measure is defined as the difference between the 75th percentile and the 25th percentile. I.e., it is the range of the middle 50% of the distribution.
Note - this measure of variability is used when the median is used as the measure of central tendency (as opposed to the mean).
Percentile definition: the score that has a specified percentage of the cases below it.
Range definition: the highest score minus the lowest score.
This type of sampling is based on ease of access or availability to the researcher, such as people on a street corner or students in a class. While convenient, this method may not accurately represent the broader population.
What is convenience sampling?
Note - this a type of non-probabilistic (aka non-random) sampling.
This type of data is:
1) on a continuum
2) in ranked order
3) has an equal distance between ranks
4) has an absolute or meaningful 0
What is ratio data?
These terms describe distributions have one "hump", 2 "humps", or 3 "humps".
What are unimodal, bimodal, and trimodal?
Note: unimodal is by far the most common.
Question: what could cause a bimodal or trimodal distribution?
This measures the dispersion (or variability) of a set of numbers, giving a set distance from the mean in a normal distribution.
What is the standard deviation?
Note - it quantifies how spread out the values are from the mean. A small standard deviation = a narrow "hump" and a large deviation = a wide "hump".
This type of sampling is when every member of the population has an equal chance of being selected. This can be achieved using random number tables or computerized random number generators.
What is simple random sampling?
Note - this is a type of probabilistic (aka random) sampling. This approach aims to produce a sample that is representative of the population, allowing for the generalization of results to the wider population.
This type of data is:
1) categorical
2) in ranked order
3) has distances between ranks that are NOT equal
What is ordinal data?
This type of distribution is a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean.
What is a normal distribution?
These are the percentages of cases that fall within:
1) +- one standard deviation of the mean
2) +- two standard deviations of the mean
3) +- three standard deviations of the mean
What are 1) 68%, 2) 95%, 3) 99.7%?
Note - knowing these percentages can allow researchers to quickly assess if their data follow a normal distribution pattern.
It also allows for the comparison of scores or data across different scales by transforming them into a common scale based on their deviation from the mean, facilitating comparisons between datasets or groups.