Stats A

Unit One—Vocabulary

What is Statistics?

• The science of collecting, organizing, analyzing, and interpreting data in order to make decisions

Data:

• Information from observing counts, measurements, or responses.

Data Sets:

• Population: Collection of all outcomes, responses, measurements, or counts that are of interest

• Sample: Subset—a part of—a population.

Practice 1: A business school researcher wants to know what factors affect the survival and success of small businesses. She selects a sample of 150 restaurants from those listed in the phone book for a large city. Identify the population and sample.

• Population: All of small businesses in the city

• Sample: 150 restaurants

Practice 2: A truckload of apples arrives at an apple juice production plant. The plant’s quality control team selects three large buckets of apples from various locations within the truck. These apples are selected carefully. Based on inspection results, the entire truckload is either accepted or rejected by the plant. Identify the population and sample.

• Population: Truckload of apples

• Three large buckets of apples.

Parameter:

• Numeric description of a population characteristic.

Statistic:

• Numeric description of a sample characteristic.

Practice 3: A recent survey by the alumni of a major university indicated that the average salary of 10,000 of its 300,000 graduates was 125,000. Is this a parameter or a statistic?

• This is a statistic

Practice 4: The average salary of all assembly-line employees at a certain car manufacturer is $33,000. Is this a parameter or a statistic?

• This is a parameter

Practice 5: The average late fee for 360 credit card holders was found to be $56.75. Is this a parameter or a statistic?

• This is a statistic

Two Branches of Statistics

• Descriptive Statistics: Involves the organization, summarization, and display of data.

• Inferential Statistics: Involves using a sample to draw conclusions about a population—probability (Chapter 3)