Cumulative Frequency and Quartiles

The video tutorial explains cumulative frequency, a method of accumulating data as it progresses. It covers how to plot cumulative frequency graphs, emphasizing the importance of plotting the top point rather than the midpoint. The tutorial also demonstrates how to find the median and interquartile range from these graphs. Additionally, it provides guidance on estimating values and interpreting data from cumulative frequency graphs, using examples to illustrate these concepts.

What is cumulative frequency?

• The difference between frequencies

• The average of frequencies

• A running total of frequencies

• A total of all frequencies

When plotting a cumulative frequency graph, which number should be plotted?

• The top number

• The midpoint

• The bottom number

• The average number

How do you find the median from a cumulative frequency graph?

• By finding the highest point on the graph

• By locating the middle value on the graph

• By calculating the average of all values

• By finding the lowest point on the graph

What is the median if the total frequency is 60?

• 30

• 60

• 15

• 45

What is the interquartile range?

• The range between the highest and lowest values

• The range between the upper and lower quartiles

• The average of all quartiles

• The sum of all quartiles

How do you calculate the lower quartile?

• By dividing the total frequency by 4

• By subtracting the upper quartile from the total

• By finding the median

• By adding all frequencies

What is the upper quartile if the total frequency is 70?

• 17.5

• 70

• 52.5

• 35

How can you estimate the number of people more than a certain time late?

• By adding all the frequencies

• By looking at the starting point of the graph

• By finding the difference between the total and the cumulative frequency at that time

• By calculating the average time

If 56 people have arrived by 42 minutes, how many more are expected?

• 14

• 28

• 42

• 56

How do you find the number of people more than 46 minutes late?

• By multiplying the cumulative frequency at 46 minutes by 2

• By adding the cumulative frequency at 46 minutes to the total

• By subtracting the cumulative frequency at 46 minutes from the total

• By dividing the cumulative frequency at 46 minutes by 2