Making Statistical Inferences

A sample should be

• representative of  only middle school students only

• a very large group

• representative of the population

• representative of people who volunteer

Zoie completes a report by asking 70 students across campus. She found that 48% of CIAA students do not wash their hands after using the bathroom. What is the population of her survey?

• the bathroom

• CIAA students

• 48% of students

A recent survey of 800 seventh graders from across the state shows 4 out of 10 like to play paper football. How many students said they like to play paper football?

• 40 students

• 200 students 

• 320 students

• 8,000 students

_______ is a part of a group being surveyed.

• Sample

• Population

• Random Sample

• Quartile

A representative sample of 80 customers in a clothing store was surveyed about how they paid for their purchases. The table shows the responses. Based on the results, which of the following are valid inferences. Select all that apply.

• Tomorrow, 8 out of the first 80 customers will for sure pay with a gift card.

• In a group of 40 customers, it is expected that about 10 will pay with cash.

• About 0.3, or 30%, of all the store's customers will pay with a credit card.

• A sample of 100 customers would provide less reliable data.

A representative sample of 80 customers in a clothing store was surveyed about how they paid for their purchases. The table shows the responses. Based on the results, which of the following are valid inferences. Select two answer choices.

• Tomorrow, 8 out of the first 80 customers will for sure pay with a gift card.

• In a group of 40 customers, it is expected that about 10 will pay with cash.

• About 30% of all the store's customers will pay with a credit card.

• A sample of 100 customers would provide less reliable data.

Sam tested every 50th candy bar from the assembly line to make sure there were enough peanuts in each bar.  He found 15% did not have enough peanuts.  How many candy bars do not have enough peanuts if the factory produces 20,000 candy bars?

• 300

• 3,000

• 300,000

• 50

The manager of a music store surveyed a random sample of customer who shop in the store about their favorite type of music. The table shows the number of customers who selected each type of music. Based on the information in the table, which inference about the favorite type of music of all the customers who shop in the music store appears to be valid?

• They are certain to select rock or pop music.

• They are less likely to select country or rap music than rock music.

• They are more likely to select country music than jazz, classical, or rap music.

• They are certain to select any type of music other than jazz music.

Sampling can be used to make an inference (or educated guess) about a population.

• True

• False

The table shows the monthly sales at a pizza parlor for a 6-month period. Which statement is the best inference that can be made from the table?

• January had the lowest sales.

• The period with the greatest increase in monthly sales was from May to June.

• Sales for July will be greater than $10,000.

• The sales will drop over the next 2-month period.