AP Psychology - Unit 0.3 Data Interpretation

Descriptive Statistics

• manage and make sense of raw data

• organize and describe collected data

Range

highest value point subtracted by the lowest value point

Inferential Statistics

• make predictions about data and independent variables

• determines if results from a sample can be generalized to a larger population

Standard Deviation

• how data varies as it relates to the mean

• allows researchers to indicate the average distance from the mean for a data set

Null Hypothesis

• claims there is no effect nor difference between variables

• serves as a baseline for testing

Normal Distribution

• represented by a symmetrical, bell-shaped curve

• only one mode

• mean, median, and mode are all located at the center of distribution

• not the most common frequency distribution

Alternate Hypothesis

• claims that there is an effect of difference between the variables

• does not necessarily have to agree with your hypothesis

Positive Skewed Distribution

• median and mode are less than the mean

• scores are low and are clustered towards the left

P-Value

• provide insights on the statistical significance

• if p value < 0.05, experiment is significant and null hypothesis is rejected

Negative Skewed Distribution

• median and mode are greater than the mean

• scores are high and are clustered to the right

Effect Size

• demonstrates the strength or meaningfulness of the relationship between two variables

• more specific than p-value

Bimodal Distribution

• two modes

• two bell-curves

Statistical Significance 

• the probability that what happened in an experiment or the difference of variables did not occur by chance

Z-Score

• numerical measurement that describes how many standard deviations a particular score is from the mean

Frequency

• how often you see a particular data point

Percentile Rank

• percentage of scores at or below a particular score

Distribution Table

• allows scientists to see how often you see a particular data point

Correlational Study

• non-experimental research method

• studies seek to determine the relationship between variables

• DOES NOT DETERMINE CAUSATION

Frequency Polygon

• visual representation of a frequency distribution table

• a line graph

Correlation Coefficients

• represented by the letter r (r-value)

• determines strength and direction of correlation

Histogram

• displays data as a bar graph

Positive Correlation 

• as one variable increases, the other also increases

Mean

the average of the data set

Mode

value that is repeated the most

Median

value that is at the exact middle of the data set

Negative Correlation

• as one variable increases, the other decreases

• shows an inverse relationship

Regression To The Mean

• occurs when outliers (very high or low results) are followed by results closer to the average

• more data point there are, the more that will be closer to the mean

Central Tendency

• the idea that data points tend to be around the mean

Measures Of Variability

• quantifies the dispersion of data

• data points in relation to the mean

• includes measurements such like range and standard deviation