Explanation:

 The Consumer Price Index (CPI) is a measure that examines the weighted average of prices of a basket of consumer goods and services, such as transportation, food and medical care. It is calculated by taking price changes for each item in the predetermined basket of goods and averaging them. Changes in the CPI are used to assess price changes associated with the cost of living; the CPI is one of the most frequently used statistics for identifying periods of inflation or deflation.
What Is in the CPI?
The CPI statistics cover professionals, self-employed, poor, unemployed and retired people in the country. People not included in the report are nanometre populations, farm families, armed forces, and people serving in prison and those in mental hospitals.
The CPI represents the cost of a basket of goods and services across the country on a monthly basis. Those goods and services are broken into eight major groups:
• Food and beverages
• Housing
• Apparel
• Transportation
• Medical care
• Recreation
• Education and communication
• Other goods and services.