Descriptive Statistics

Slide 1

Basic Math and Key Measures
There are 5 easy to compute measures to derive meaning in most data analysis situations. percentage average median mode  standard deviation

Slide 2

Percentage
The use of percentages for the analysis of survey data works exactly as you'd expect. Divide the number of people who give a specific response by the total number of people answering the question. Once you calculate the percentages for each type of response, you can chart them  The total of the percentages should add up to 100%    

Slide 3

Averages
You probably remember this from your classes. Your class average summarizes your performance in the class.  Averages are useful to summarize responses to a particular survey question Divide the total number of points for the question by the total number of people answering the question   

Slide 4

Median and Mode
the median is the number that appears in the middle of an ordered set of data (lowest to highest) useful when an average is skewed by a very high/low response the mode is the number that occurs most often useful to find the most frequent response    

Slide 5

Standard Deviation
Dispersion refers to how spread out/clustered a set of scores is around the mean Standard deviation is a way to understand and compare distribution of scores without having to actually plot and examine each and every score When comparing standard deviations, any particular standard deviation is a reflection of the underlying scale Standard deviations cannot be compared when scales have different numbers of options Look at page 403 for the standard deviation formula This is what SPSS is used for...

Slide 6

MAKE SURE YOU HAVE GOOD DATA
Clean up your data and fact check it check responses to see if the are responses that are: missing  inappropriate unexpected odd  

Slide 7

Checklist questions
Given positive/negative items on a checklist, only 3 patterns of responses are possible -all positive (positive person) -all negative (negative person) -both positive and negative (mixed feelings)

Slide 8

Subgroup Analysis
analyzing subgroups provides deeper insights can take to any level of detail think about the data from the research end user's perspective look for the unexpected be open-minded be sensitive to sample size

Slide 9

Data Analysis
demographic information: age  gender purchase intent commercial believability commercial uniqueness reaction to commercial (two checklist items)

Slide 10