Introduction to Statistics

Primary Data Versus Secondary Data

Primary data is collected by:

• people doing it for the first time

• gathering data already done by other people

• primary school kids

• people who will be using it

Descriptive statistics is

• the collection, condensation and display of information

• about decision making and drawing conclusions from the data

• the collection of primary data

• the collection of secondary data

Inferential statistics is

• the collection, condensation and display of information

• about decision making and drawing conclusions from the data

• the collection of primary data

• the collection of secondary data

Primary Data Versus Secondary Data

Only ONE of the following is a study of the population

• Albert, Director of Human Resources, is studying the records of all employees who worked at HSBC to exploring the causes of high employee absenteeism

• Albert, Director of Human Resources, is exploring the personnel records for 50 of the plant's 250 employees to help explain the causes of employee absenteeism at HSBC

• Susan, Chief Financial Officer of Harrison, Inc., suspects irregularities in the payroll system, and orders an inspection of "every tenth payroll voucher issued since January 1, 1999."

• The Human Resources Director of a large insurance company wishes to develop an employee health benefits package and decides to select 400 employees from a list of employees in order to study their preferences for the various components of a potential package.

Inferential Versus Descriptive Statistics.

Only ONE of the following is an example of descriptive statistics.

• The collection and summary of graduate degrees and research areas of interest of the faculty in the University of Michigan of a particular academic institution.

• The estimation of the population average student expenditure on education based on the sample average expenditure of 1,000 students.

• Twenty-five percent of a sample of 200 tennis players indicated that their parents did not play tennis. Based on this sample, we estimate that the 25% figure holds for the parents of all professional tennis players.

• You asked five of your classmates about their height. On the basis of this information, you stated that the average height of all students in your university or college is 65 inches

Primary Data Versus Secondary Data

Secondary data is collected by:

• people doing it for the first time

• gathering data already done by other people

• primary school kids

• people who will be using it