Population and Sample Estimate

Identify the population and sample.

A survey of 1535 American households found that 18% of households do not own a computer.

• Population: 1535 American households

  Sample: 18% of households

• Population: All American households

  Sample: 1535 American households

• Population: All American households

  Sample: 18% of households

• Population: 1535 American households

  Sample: 276 households

Identify the population and the sample.

• Population: All elementary school children

  Sample: 2625 elementary school children surveyed

• Population: All elementary school children

  Sample: 28% of the children

• Population: 2625 elementary school children

  Sample: 28% of the children

• Population: 2625 elementary school children

  Sample: 735 elementary school children

True or False: all samples lead to a good prediction about an entire population.

• True

• False

Mrs. Boyd wants to find the average height of all her students in her classes. She decides to use the first 5 people who walk in the door. Is this a good representative sample?

• Yes

• No

Population or Sample?

A factory overseer selects 40 threaded rods at random from those produced that week at the factory, then she tests their tensile strength.

• Population

• Sample

A quality control engineer is curious about the thickness of paint on a car at her factory. She randomly selects 30 points on the car and measures the paint thickness at each of those points.

• The population is every possible point on the car; the sample is the 30 selected points.

• The population is every car at the factory; the sample is the 1 car she is curious about.

• The population is every car at the factory; the sample is the 30 selected points.

The entire pool; the total set of people/objects that can be studied

• population

• sample

• datum

• probability

Which sampling technique involves selecting every nth subject in a population?

• Simple Random Sample

• Stratified

• Cluster

• Systematic

What is a point estimate?

• average of sample values

• average of population values

• a single value that represents the unknown sample statistic

• a single value that represents the unknown population parameter

The scores of a random sample of 100 high school students on a standardized mathematics test in school A gave a mean of 78 and a standard deviation of 20. What is the best point estimate of the true average score in this standardized mathematics test?

• 20

• 78

• 95

• 100