Key Definitions

1. Key Definitions • Population: • the entire collection of individuals or objects about which information is desired is called the population of interest. • Sample: • A sample is a subset of the population, selected for study in some prescribed manner.

2. Key Definitions (continued) • Observation units: objects described by a set of data. • Variable: any characteristic of an observation unit. • Graph displays (bar graph and dotplot) • Quantitative variable: center & spread

3. Problem 1.6 on page 11 of textbook • The supervisors of a rural county are interested in the proportion of property owners who support the construction of a sewer system. Because it is too costly to contact all 7000 property owners, a survey of 500 owners (selected at random) is undertaken. Describe the population and sample for this problem.

4. Problem 1.8 on page 11 of textbook • A consumer group conducts crash tests of new model cars. To determine the severity of damage to 2006 Mazda 6s resulting from a 10-mph crash into into a concrete wall, the research group tests six cars of this type and assesses the amount of damage. Describe the population and sample for this problem.

5. Problem 1.11 on page 19 of textbook • Classify each of the following attributes as either categorical or numerical. For those that are numerical, determine whether they are discrete or continuous. • Brand of computer purchased by a customer • State of birth for someone born in the United States • Price of a textbook

6. Problem 1.11 & 1.13 (continued) • Concentration of a contaminant (micrograms per cubic centimeter) in a water sample • Zip code • Actual weight of coffee in a 1-lb can • The length of a 1-year old rattlesnake • The price per gallon paid by the next customer to buy gas at a particular station