Understanding Group Frequency Tables

The video tutorial explains how to calculate the mean of a group frequency table using grade intervals and frequencies. It covers the process of estimating the mean by calculating midpoints for each interval and multiplying them by their respective frequencies. The tutorial also discusses how to determine the median and mode, and provides a practice example using student weights.

What is the purpose of the frequency column in a group frequency table?

• To determine the highest grade

• To show the number of students in each grade range

• To list the grades of students

• To calculate the total number of students

Why can't an exact mean be calculated from a group frequency table?

• Because the intervals are too large

• Because the midpoints are not accurate

• Because individual data values are unknown

• Because the frequency column is missing

How is the midpoint of a grade interval calculated?

• By subtracting the lower boundary from the upper boundary

• By averaging the lower and upper boundaries

• By dividing the upper boundary by the lower boundary

• By adding the frequency values

What is the formula for estimating the mean in a group frequency table?

• Sum of frequencies times intervals divided by midpoints

• Sum of midpoints divided by number of intervals

• Sum of frequencies divided by number of intervals

• Sum of frequency times midpoint divided by sum of frequencies

In which interval is the mean likely to be found if most students scored between 70 and 79?

• 70 to 79

• 60 to 69

• 80 to 89

• 90 to 100

Where is the mode located in a group frequency table?

• In the interval with the median value

• In the interval with the highest frequency

• In the interval with the lowest frequency

• In the interval with the smallest range

How is the cumulative frequency calculated?

• By multiplying the frequencies by the midpoints

• By adding the frequencies sequentially

• By dividing the total frequency by the number of intervals

• By subtracting the lower boundary from the upper boundary

What is the midpoint for the interval 200 to 220?

• 220

• 205

• 215

• 210

In the practice example, which interval contains the median?

• 120 to 139

• 140 to 159

• 160 to 179

• 180 to 199

What is the mean weight in the practice example?

• 210

• 165.7

• 129.5

• 149.5