Biased and Unbiased samples

A teacher selects 30 students out of 300 students in grade 6, to participate in a survey about recycling. She asks first 30 students that enters her classroom. Of the 30 students, 25 students refills their water bottles. How many students will refill the bottle?

• 250

• 350

• 500

• 450

Saeed is surveying his friends to find what sports they like. Saeed wants to ask 50 friends. Instead he decides to ask every  $5^{th}$  friend that arrives into school. 

From a sample of 10 friends. 6 of his friends like boxing. What is the sampling method used and prediction of saeed's friend?

• Unbiased Systematic, 30

• biased voluntary, 30

• biased convenience, 45

• Unbiased simple random, 45

The last 20 people that were leaving a mall on a single day were asked about their favorite hobbies.

In total, 1000 people entered the mall. 17 people said they like shopping.

From the sample, how many people can we predict would also like shopping.

• 85

• 50

• 850

• 120

The local gym is deciding if customers that want more gym classes. The gym surveys 50 gym customers a day. How could the gym improve their sampling method?

• Ask 60 customers

• Go to mall and ask 50 people

• Ask every $5^{th}$ person that arrives to the gym

• Ask the first 5 customers

A teacher wants to know how many hours it will take for all students at the school to complete their work. She asks first 5 Students to enter her classroom. What type of sampling is it?

• Simple Random

• Convenience

• Systematic

• Voluntary

Every 3^rd student as they enter the school, is surveyed to determine students' favorite color. Describe the type of sampling used.

• Simple Random

• Convenience sampling

• Voluntary

• Systematic

Which sampling method will give the most unbiased results, if you wanted to find the number of people in your school that spent more than 4 hours completing their homework.

• Ask 30 students in Math and science class

• Ask 30 people that you meet at the mal

• Ask 30 random students from your school of different ages

• Ask 30 friends

Ahmed invites all his 30 friends to come and play at his house.

Ahmed surveys 5 friends, asking their favorite game.

3 of 5 friends say football game.

How many friend will chose football game?

A systematic random sample of 50 customers was taken, at desserts shop.

In a single day, the shop had 650 customers.

These 50 customers were asked their favorite dessert.

If 25 of 50 said ice cream, how many customers should we expect to name ice cream as their favorite dessert.

Maha surveys her class about their favorite food.

A simple random sample of 10 girls, from a class of 35 girls used in this survey.

If 4 of the 10 girls said burgers, how many students from the class of 35 students can we expect to name burger as their food.