Question

write the formula to find mode and median for grouped data ​

Answer 1

Answer:

To find the Median Alex places the numbers in value order and finds the middle number.



In this case the median is the 11th number:

53, 55, 56, 56, 58, 58, 59, 59, 60, 61, 61, 62, 62, 62, 64, 65, 65, 67, 68, 68, 70

Median = 61 

To find the Mode, or modal value, Alex places the numbers in value order then counts how many of each number. The Mode is the number which appears most often (there can be more than one mode):

53, 55, 56, 56, 58, 58, 59, 59, 60, 61, 61, 62, 62, 62, 64, 65, 65, 67, 68, 68, 70

62 appears three times, more often than the other values, so Mode = 62

Grouped Frequency Table

Alex then makes a Grouped Frequency Table:

SecondsFrequency51 - 55256 - 60761 - 65866 - 704



So 2 runners took between 51 and 55 seconds, 7 took between 56 and 60 seconds, etc