Ap B Flashcards
Define descriptive statistics.
Statistics used to describe and summarize data collected in research.
Define inferential statistics.
Statistics used to draw conclusions about research data.
What is a frequency distribution?
A summary that shows the frequency of different scores or categories in a dataset.
What is an ungrouped frequency distribution?
A count of the number of times each unique score occurs in a dataset.
What is a grouped frequency distribution?
A count of the number of times scores fall into specific ranges or classes in a dataset.
How can you identify the highest and lowest scores using a frequency distribution?
By observing the first and last entries in a sorted list of scores or by checking the frequencies in the distribution.
What is a histogram?
A bar chart representing the frequency of specific data points in a dataset, often used for ungrouped frequency distributions.
What is the benefit of using a grouped frequency distribution?
It simplifies the data by reducing the number of unique categories, making it easier to analyze larger datasets.
What does a histogram’s x-axis represent?
The ordered listing of the various values or scores.
What does a histogram’s y-axis represent?
The frequency of the scores.
What is a frequency polygon?
A line graph depicting a grouped frequency distribution, created by connecting the midpoints of each class of data.
How do you calculate midpoints for a frequency polygon?
The midpoint is calculated as the average of the upper and lower bounds of each class.
What are measures of central tendency?
Numbers used to summarize data sets, such as the mean, median, and mode.
What is the mean?
The average value in a data set, calculated by summing all values and dividing by the number of items.
How do you calculate the median?
Order the data from smallest to largest and find the middle value; if even, take the average of the two middle values.
What is the mode?
The most frequently occurring score or value in a data set.
How is the range calculated?
The range is the difference between the largest and smallest values in a data set.
What is variance?
A calculated indicator of how much values in a data set differ from the mean; the average of squared deviations from the mean.
What is the standard deviation?
The square root of the variance, providing a measure of how much scores vary within a group in the same metric as the original data.
What is a normal distribution?
A symmetrical, bell-shaped distribution where most scores cluster around the mean, with fewer scores at the extremes.
What does the peak of a normal distribution represent?
The mean, median, and mode of the distribution, where most values are concentrated.
What does it mean that a distribution is positively skewed?
Most values occur at the lower end of the scale, with a few high scores pulling the mean upward.
What is a negatively skewed distribution?
A distribution where most values occur at the upper end of the scale, with a few low scores pulling the mean downward.
What are measures of association?
Descriptive statistics that quantify and summarize the degree of relationship between variables.
What is a random sample?
A sample in which every member of the population has an equal chance of being selected.
What is the purpose of random assignment in experiments?
To ensure that any differences between experimental and control groups are evenly distributed, making the groups as similar as possible.
What is hypothesis testing?
A statistical method to test a statement or claim about a population using sample data, focusing on experimental and control group differences.
What does the null hypothesis assert?
That there is no difference between the average performance of individuals in one group compared to another.
What does the alternative hypothesis propose?
That there is a difference between the average performance of individuals in one group compared to another.
What is a sampling distribution?
The theoretical distribution of a sample statistic, such as the difference between two sample means from a population.
What is an effect size?
A standardized measure that reflects the degree of relationship or size of the difference between two or more variables.
What is Cohen’s d?
A common effect size measure that quantifies the standardized difference between two population means.
