Stats - Midterms

• Statistics - Science of collecting, organizing, analyzing and interpreting data in order to make decisions
• Data - Information coming from observations, counts, measurements or responses
• Population - All members that forms a data set
• Sample - Few members of the population
• Sample - Taken to represent certain traits of population
• Parameter - Value obtained from population
• Statistic - Value obtained from Sample
• Descriptive Statistics - uses date to provide descriptions of the population
• Descriptive Statistics - Common tools are Measure of Central Tendency and Variability
• Inferential Statistics - Involves using sample data to draw conclusion about a population
• Inferential Statistics - Common tools are Hypothesis testing and Regression Analysis
• Qualitative Data - Non-numerical entries
• Quantitative Data - Numerical measurements
• Discrete Variable - Countable
• Continuous Variable - Measurable
• Nominal - Calculated using names, qualitative only
• Ordinal - Arranged in order but difference in data are not meaningful
• Interval - A zero entry represents a position on a scale; the entry is not inherent zero
• Interval - zero may indicate no difference instead of absolute absence
• Ratio - Similar to interval but zero entry is meaning
• Ratio of two data values can be formed so one data value can be expressed as a ratio
• When a value of zero is present, it indicates that nothing is actually there
• Observational - Observes and measures part of a population
• Experimental - Treatment is applied in part of population
• Simple Random Sample - Each have an qual chance of being selected
• Stratified Sample - Population is divided into strata then take a sample from each stratum
• Cluster Sample - Population is divided into strata then select one strata as the sample
• Systematic Sample - Select a starting point and take every n-th piece of data
• Convenience Sample - Selecting any member who are convenient and available
• Central Tendency - Measures, describes the middle or center of data. Also a value to represent a set of scores/frequencies
• Mean/Average [x̄] - The given values in a distribution divided by the number of observations
• Median [md] Measures the centered of an ordered data set by dividing it into two equal parts
• Mode [mo] - Data entry that occurs with the greatest frequency
• Measure of Variability - Measure of spread, number that measures how spread out a data set is along the x-axis
• Dispersion - Difference between the actual value and average value
• Range - Difference of the highest and lowest value in the data set
• Variance - Mathematical expectation of the average squared deviations from the mean
• Standard Deviation - Used to tell how measurements for a group are spread out from the average
• Standard Deviation - Calculated as the square root of variance
• Measures of Position - Also called Measured of Relative Standing