Using Sampling to Predict Practice

Identify each sample as biased or unbiased and describe its type:

To determine how many students have pets, all students in one classroom are surveyed.

• Biased - Convenience Sample

• Unbiased - Random Sample

• Biased - Voluntary Response Sample

• Unbiased - Systematic Sample

Identify each sample as biased or unbiased and describe its type:

To determine the number of students who plan on attending the Valentine’s Day dance, 20 students are randomly selected from each grade level.

• Biased - Convenience Sample

• Biased - Voluntary Response Sample

• Unbiased - Stratified Random Sample

• Unbiased - Simple Random Sample

Identify each sample as biased or unbiased and describe its type:

To determine whether customers are satisfied with their meals, a restaurant collects comment cards that are voluntarily filled out by customers.

• Biased - Voluntary response sample

• Unbiased - Simple random sample

• Biased - Convenience sample

• Unbiased - Systematic sample

Identify each sample as biased or unbiased and describe its type:

To determine the most popular color of car, the color of every 12th car that crosses an intersection is recorded.

• Unbiased - Systematic Sample

• Biased - Simple Random Sampling

• Biased - Convenience Sampling

• Unbiased - Stratified Sampling

Identify each sample as biased or unbiased:

To determine the most popular major league baseball team among its readers, a sports magazine polled by telephone a random selection of its readers. This sample is:

• Biased

• Unbiased

The student council would like to sell pizza slices during home basketball games as a fundraiser. During a home game with 250 people in attendance, they surveyed every 10th spectator to enter the gym about their favorite pizza toppings. Their results are shown in the table. Is this sampling method valid? If so, how many pepperoni pizzas should be ordered if they order 25 pizzas? Explain your reasoning.

• Yes, the sampling method is valid. Order 10 pepperoni pizzas.

• No, the sampling method is not valid. Order 10 pepperoni pizzas.

• Yes, the sampling method is valid. Order 8 pepperoni pizzas.

• No, the sampling method is not valid. Order 8 pepperoni pizzas.

Identify each sample as biased or unbiased and choose the correct reasoning:

To determine how many people in a town support a new tax levy, 200 people are randomly selected from a phone book and then surveyed over the phone.

• Biased - The sample is not representative of the entire town as it only includes people with listed phone numbers.

• Unbiased - The sample is randomly selected and large enough to represent the entire town.

• Biased - What's a phone book?

• Unbiased - The sample size is large enough to represent the entire town.

Identify each sample as biased or unbiased and describe its type:

To determine the number of households in a town that recycle, 40 households from the same street are polled.

• Biased - Convenience Sample

• Unbiased - Random Sample

• Biased - Voluntary Response Sample

• Unbiased - Systematic Sample

Identify each sample as biased or unbiased and describe its type:

To determine the usual demand of a Web site, the number of users currently visiting the Web site is recorded every hour.

• Biased - Convenience Sample

• Unbiased - Random Sample

• Biased - Voluntary Response Sample

• Unbiased - Systematic Sample

Identify each sample as biased or unbiased and describe its type. The yearbook staff wanted to find out how many students would buy a yearbook. So, the staff surveyed 15 students who were in the school library after school. The results are in the graph. Is this sampling method valid? If so, about how many of the 1287 students in the school will buy yearbooks?

• A) The sampling method is valid, and approximately 300 students will buy yearbooks.

• B) The sampling method is valid, and approximately 600 students will buy yearbooks.

• C) The sampling method is biased, so you cannot come to a reasonable conclusion.

• D) The sampling method is biased, and approximately 600 students will buy yearbooks.