1. Summary Statistics

What is Statistics?

• The field of statistics : the practice and study of collecting and analyzing data
• Two main branches of statistics:
  • Descriptive/Summary statistics - describing or summarizing our data
  • Inferential statistics - collect a sample of data, and apply the results to the population that the sample represents.
• allows us to answer practical questions:
  • average salary in the USA
  • customer inquiries is a company likely to receive per week?
• applications
  • developing safer products such as cars or airplanes
  • help governments understand the needs of a population
• validates scientific breakthroughs

Limitations of statistics

• statistics requires specific, measurable questions:
  • Statistics requires specific, measurable questions
  • requires specific measuaranle questions
  • We can’t use statistics to find out why relationships exist,

Numeric

• continuous data: interval or count data
• How Visualizing numeric data

Categorical

• nominal
  • eye color
• ordinal data
  • how strongly do you agree

Inferential statistics

• use a sample to draw conclusions about a population
• how many people purhcase clothing?