Understanding the Five Number Summary and Quartiles

The video tutorial explains the five number summary of a data set, which includes the minimum, quartile one, median (quartile two), quartile three, and maximum. These values divide the data into four equal parts, each containing 25% of the data. The tutorial further explores the percentage of data values at or below quartile one (25%), quartile three (75%), and the median (50%). It provides examples using test scores to illustrate these concepts, including calculations for data at or above quartile one.

What does the five number summary of a data set include?

• Quartile one, quartile two, quartile three, mean, mode

• Minimum, maximum, mean, mode, range

• Mean, mode, median, range, standard deviation

• Minimum, quartile one, median, quartile three, maximum

What is the median also known as in the five number summary?

• Maximum

• Quartile three

• Quartile two

• Quartile one

Which part of the five number summary divides the data into four equal parts?

• Quartiles

• Mean

• Mode

• Range

How much of the data set lies at or below the first quartile?

• 100%

• 75%

• 25%

• 50%

What percentage of data values lie at or below the third quartile?

• 25%

• 100%

• 75%

• 50%

Which quartile represents the 75th percentile of the data?

• Quartile two

• Quartile three

• Quartile one

• Maximum

In a sample of 240 test scores, how many scores are at or below the median?

• 240

• 60

• 120

• 180

How do you calculate the number of scores at or below a quartile in a sample?

• Divide the total number of scores by the quartile percentage

• Add the total number of scores to the quartile percentage

• Subtract the quartile percentage from the total number of scores

• Multiply the total number of scores by the quartile percentage

If a sample consists of 2000 test scores, how many are at or above the first quartile?

• 500

• 1000

• 1500

• 2000

What is the percentage of data values at or above the first quartile?

• 50%

• 75%

• 100%

• 25%