Understanding Inferences from Random Samples

What is the main purpose of making inferences from a random sample?

• To compare two different populations

• To identify errors in data collection

• To make predictions about a population based on a sample

• To determine the exact number of items in a population

In the dot plot example, what is the most common number of books carried by students?

• Four

• Six

• Two

• Zero

What is a key advantage of using dot plots?

• They show the median clearly

• They organize data and show frequency

• They are easier to draw than box plots

• They require less data

How can Rosie improve the quality of her data?

• By reducing the sample size

• By asking more students

• By using a different type of plot

• By only asking students with more than three books

What does the median represent in a box plot?

• The average value of the data set

• The most frequently occurring value

• The middle value of the data set

• The range of the data set

In a box plot, what percentage of data is represented inside the box?

• 25%

• 50%

• 100%

• 75%

What does a whisker represent in a box plot?

• The minimum and maximum values

• The median of the data

• The average of the data

• The range of the middle 50% of data

What is the first step in setting up a proportion to predict defective items in a shipment?

• Find the median of the sample data

• Calculate the average number of defective items

• Determine the number of defective items in the sample

• Identify the total number of items in the shipment

If 6 out of 50 MP3 players are defective, how many would you expect to be defective in a shipment of 3500?

• 350

• 420

• 500

• 210

Why is it important for a sample to be random when making inferences?

• To ensure the sample is small

• To focus on a specific subgroup

• To avoid bias and ensure representativeness

• To make calculations easier