Introduction to Statistics

• Statistics is a science that studies data
• Statistics involves processes from collecting, processing, analyzing, interpreting and communicating data
• The word "statistics" comes from the word "state" because governments have been involved in statistical activities, especially the conduct of censuses for military or taxation purposes
• Data is a collection of facts from experiments, observations, sample surveys, censuses, and administrative reporting systems
• The frequency of a particular data value is the number of times the data value occurs
• Variable is any characteristic, number, or quantity that can be measured or counted
• A variable may also be called a data item
• Examples of variables: age, sex, business income and expenses, country of birth, capital expenditure, class grades, eye color, and vehicle type
• Two Classifications of Statistical Variable
• Qualitative variables, also called categorical variables
• Sex, marital status, ethnicity, and educational attainment are some examples of Qualitative variables.
• Collect qualitative data for questions about ideas, experiences, meanings, or something that can't be described numerically
• Quantitative variables, also called numerical variables
• Age, grades, and income are examples of quantitative variables
• Collect quantitative data for a more mechanistic understanding of a topic or research involving hypothesis testing
• Discrete variable can take on a finite number of distinct values
• The number of heads acquired while flipping a coin, the number of kin an individual has, and the number of students present in a study hall at a given time are examples of discrete variables.
• Continuous variable has an uncountable number of potential values, regularly measurable amounts
• Height or weight of an individual, the time it takes for an individual to wash, temperature, item thickness, length, age are examples of continuous variable.
• In a Nominal Scale, variables do not have any evaluative distinction and one value is not greater than the other.
• Sex, strand, and type of school are examples of variables in a nominal scale
• In a/an Ordinal Scale, there is an evaluative connotation and one value is greater or larger or better than the other
• Rating job satisfaction on a scale from 1 to 10, government positions, and socio-economic status are examples of variables in an ordinal scale
• Interval Scales give information about more or betterness as ordinal scales do, but with an equal distance between each value
• Ratio Scale has the same properties as an interval scale but with an absolute zero point
• The temperature using Celsius or Fahrenheit and the measurement of sea level are examples of variables in an interval scale
• Weight and bank account balance are examples of variables in a ratio scale
• The two types of variables are the independent variable and the dependent variable.
• Dependent variable is measured and made the object of analysis
• Independent variable is introduced, manipulated, or treated to determine if it influenced or causes change on the dependent variable
• The Two Types of Statistics are Descriptive and Inferential
• Descriptive Statistics is an analysis of data that helps describe, show, or summarize data in a meaningful way.
• Descriptive Statistics does not allow conclusions beyond the data analyzed or reach conclusions regarding hypotheses made
• Descriptive Statistics use tables, graphs, charts, and statistical commentary to describe data
• Inferential Statistics tries to reach conclusions that extend beyond the immediate data alone
• Inferential Statistics make judgments of the probability that an observed difference between groups is dependable or happened by chance
• Inferential Statistics make inferences from data to more general conditions
• This involves processes from collecting,

  processing, analyzing, interpreting and

  communicating data.

  Statistics
• What are the two classifications of a statistical variable?

  Quantitative and Qualitative
• What are the two kinds of Quantitative Data

  Discrete and Continuous