Population and Sample E

Of all U.S. kindergarten teachers, 32% say that knowing the alphabet is an essential skill.

Is the percentage a statistic or parameter?

• Parameter (from the population)

• Statistic (from the sample)

Answer explanation

The keyword "all" should clue you in that this surveyed the entire population. A statistic surveys just a portion of everyone in a population.

Of the 800 U.S. kindergarten teachers polled, 34% say that knowing the alphabet is an essential skill.

Is the percentage a statistic or parameter?

• Parameter (from the population)

• Statistic (from the sample)

Answer explanation

This surveyed just a potion of kindergarten teachers - not all of them. That means it is a statistic, not a parameter.

Of the U.S. adult population, 36% has an allergy. A sample of 1200 randomly selected adults resulted in 33.2% reporting an allergy.

Who is the population?

• All adults

• All US adults

• Adults with allergies

• 1200 randomly selected US adults

Answer explanation

Population refers to the entire group that conclusions are being made about. This is making a conclusion about the US adult population (not all adults in the world - specifically US adults) saying 36% of them have an allergy.

Of the U.S. adult population, 36% has an allergy. A sample of 1200 randomly selected adults resulted in 33.2% reporting an allergy.

What is the sample?

• All adults

• All US adults

• Adults with allergies

• 1200 randomly selected US adults

Answer explanation

Sample refers to the portion of the population surveyed. Here they surveyed 1200 random adults. Since the population is US adults, we assume the people surveyed are US adults.

Of the U.S. adult population, 36% has an allergy. A sample of 1200 randomly selected adults resulted in 33.2% reporting an allergy.

What is the statistic?

• 33.2%

• 36%

Answer explanation

Statistics are the results from samples. Since the sample was the 1200 randomly selected US adults, the statistic would be the result from them: 33.2%

Of the U.S. adult population, 36% has an allergy. A sample of 1200 randomly selected adults resulted in 33.2% reporting an allergy.

What is the parameter?

• 33.2%

• 36%

Answer explanation

Parameters are the results from entire populations. Since the population was US adults, the parameter would be the result from them: 36%

Select 90 students currently enrolled at UC Denver and ask how many years they’ve attended the university, how old they are, and if they live on campus.

What is the population?

• 90 students currently enrolled at CU Denver

• All currently enrolled students at CU Denver

Answer explanation

The population refers to the entire group you are making conclusions about. The entire group would be all students at CU Denver.

Select 90 students currently enrolled at UC Denver and ask how many years they’ve attended the university, how old they are, and if they live on campus.

What is the sample?

• 90 students currently enrolled at CU Denver

• All currently enrolled students at CU Denver

Answer explanation

The sample refers to the portion of the group that you survey. The portion surveyed are the 90 students at CU Denver.

A study reveals that there are exactly 100 Senators in the 109th Congress of the United States, and 55% of them are Republicans.

Do the data comprise a sample or a population?

• Population because it is all Senators

• Sample because it is all Senators

Answer explanation

If all members of a group are part of the study, then they represent the population. If a portion of all members are represented it is a sample. This study had all senators so it is a population.

A study reveals that there are exactly 100 Senators in the 109th Congress of the United States, and 55% of them are Republicans.

Do the results represent a statistic or a parameter?

• Statistic

• Parameter

Answer explanation

Parameters are results from studies on entire populations. Because the entire population of senators was studied, the result is a parameter.