Use the frequency chart to calculate the mean for grouped data. This process is most frequently used when the raw data i

[answerhappygod]

Use the frequency chart to calculate the mean for grouped data.
This process is most frequently used when the raw data is not
available.
X=
(f∙Xm)n , where f is the frequency and
Xm is the midpoint
of the class.
Class Limit
Class Boundary
Class Midpoint
Frequency
f*Xm
140 - 229
139.5-229.5
184.5
11
230 – 319
229.5 – 319.5
274.5
5
320 – 409
319.5 – 409.5
364.5
4
410 – 499
409.5 – 499.5
454.5
4
500 – 589
499.5 – 589.5
544.5
4
590 – 679
589.5 – 679.5
634.5
0
680 - 769
679.5 – 769.5
724.5
1
770 - 859
769.5 – 859.5
814.5
1
Totals
30
Find the sample grouped mean for the
frequency chart. X= ________
Compare the sample means calculated
from the raw sample data and from the grouped data in the frequency
chart.
Note: The mean (is always / is not always) an
actual data value.