September 5, 2013

The definition of statistics. Identify populations and samples.

How to distinguish between descriptive and inferential statistics.

Statistics is the science of collecting, organizing, analyzing, and interpreting data in order to make decisions.

Data◦Consist of information coming from observations, counts, measurements, or responses.

Population◦The collection of all outcomes, responses, measurements, or counts that are of interest.

Sample◦Is a subset, or part, of a population.

Example: The U.S. Department of Energy conducts weekly surveys of approximately 900 gasoline stations to determine the average price per gallon of regular gasoline. On January 11, 2010, the average price was $2.75 per gallon.

A. Identify the population and the sample.-The population consists of the prices per gallon of regular gasoline at all gasoline stations in the U.S.-The sample consists of the prices per gallon of regular gasoline at the 900 surveyed stations.

B. What does the sample data set consist of?-The sample data consists of the 900

prices.

Parameter◦Is a numerical description of a population characteristic.

Statistic◦Is a numerical description of a sample characteristic.

Decide whether the numerical value describes a population parameter or a sample statistic.

A recent survey of 200 college career centers reported that the average starting salary for petroleum engineering majors is $83,121. Statistic

The 2182 students who accepted admission offers to Northwestern University in 2009 have an average SAT score of 1442. Parameter

In a random check of a sample of retail stores, The Food and Drug Administration found that 34% of the stores were not storing fish at the proper temperature. Statistic

Descriptive Statistics◦Is the branch of statistics that involves the organization, summarization, and display of data.

Inferential Statistics◦Is the branch of statistics that involves using a sample to draw conclusions about a population.

Find an article that relates to sports, health, or retail. Print out the article.

Write two paragraphs on this article. ◦ In the first paragraph explain what the article is

about.◦ In second paragraph identify the population and

sample. Identify a parameter or a statistic from your article.

This is due on Friday. It can be handwritten or typed. If I can’t read it, I won’t read it!