Descriptive statistics are used to organize and summarize information or data. They allow a researcher to provide a description of what actually exists in the data. Researchers use descriptive statistics to help us reduce large amounts of data to a more manageable size. Perhaps one of the most commonly used descriptive statistic is percentages.
Are often the next stage is data analysis. Are used when a researcher wants to make predictions. They use a smaller group, or a sample to compare data to larger groups.
Measures of central tendency:
Mean, Median, Mode
Mode:The value that occurs most in a set of numbers
Measures of variability:
range, sum of squares, variance, standard deviation.
Highest number subtracted by lowest number
Sum of squares
SS= ex2- (ex)2/N
SD= SS/N-1(square rooted)
a curve in which the tail of the curve is longer on the right side of the distribution. The mean will be greater than the mode.
A curve in which the tail is longer on the left side. The mean will be less than the median or mode.
Nominal, Ordinal, interval, ratio
Nominal measurement is a simple classification. Numbers are selected and meaningless. Lowest level of measurement.
Rank-order measurement. Assigns numbers to things in such a way as to reflect relationships among things. Allows us to see hierarchal levels between groups.
Interval measurement identifies the distance between any two things that are measured. We assign numbers to things in such ways that the distance between any two things is measured. They are probably the most common measures used by scientists.
A ratio scale has all of the characteristics of an interval scale, but in addition it has a true zero point as its origin. In ratio measurements, zero has an absolute value of its own.
Conceptualization and Operationalization
Conceptualization- Clearly defining your variables.
Operationalization: Process of measuring what you conceptualize. A good operationalization is like a recipe card. It tells you a very detailed procedure and what to do and when to do it.
the process of systematic observation and assignment of numbers to phenomena according to rules.