Question

A group of scientists have been studying a population of sea stars over 100 years. In year 1900 a scientist measured the arm length (cm) of 11 sea starts. Then in year 1950 another scientist measured the arm length(cm) of 11 new sea stars. Then in year 2000 another scientist measured the arm length(cm) of 11 new sea stars. You have access to their work and will be assisting the scientists by charting their findings and answering questions about the data they have collected.
Fill in frequency table: The Data Table gives the arm lengths(cm) for a sample of sea stars in a given year. Using the arm length(cm) from the Data Table, count the number of sea stars that fall in each size range. The first three numbers in year 1900 have been filled in for you.

Answer 1

Answer:

Size range(cm)    Year 1900     Year 1950     Year 2000

    51 - 60                    1                    0                     0

    61 - 70                    1                     1                     0

    71 - 80                   2                    2                     2

    81 - 90                   2                    5                     7

    91 - 100                  2                   3                     2                

   101 - 110                  3                    0                    0

Explanation:

Your data table is actually color-coded, so all you needed to do was count. Looking at your frequency table, you can see that a color corresponds to certain colors.

For example 51 - 60c, corresponds to the light green. Looking at the data table, you see 1 light green block in the column of 1900. As it happens, it also is the only measurement that falls within the range 51 - 60 so you have 1 sea star. In the Year 1950, there is none, and you won't find one in Year 2000, so both frequency count is 0.