Question

the following data represents the CGPA of students:
2.55 2.86 2.79 2.95 2.56 2.86 2.96 2.56 2.64 2.98 2.35 2.59 2.89 2.95 2.86 2.96 2.91 2.79 2.94 2.86 2.95 2.99 2.5 2.86
3.51 3.08 3.34 3.15 3.37 3.23 3.67 3.35 3.75 3.09 3.40 3.50 3.02 3.43 3.23 3.14 3.18 3.14 3.2 3.04 3.25 3.18 3.28 3.11 3.31 3.04

construct a grouped frequency??

Answer 1

i try to solve it by
find the range
range = 3.75 - 2.35 = 1.4

Answer 2

then for the width i choose a class from 5 to 25 , so i select 7
therefore the width will be
width = 1.4/7

Answer 3

width 1.4/7 = 0.2
by subtract 0.005 from lower limit and add 0.005 to higher limit i get boundaries
class limits class boundaries
2.35-3.34 2.345-3.345
3.35-4.34 3.345-4.345
4.35-5.34 4.345-5.345
5.35-6.34 5.345-6.345
6.35-7.34 6.345-7.345
7.35-8.34 7.345-8.345
8.35-9.34 8.345-9.345

when I try to write the tally for frequency, i found that all frequencies will be in first two classes....it get confuse....
any one have idea for that???????????????????????????
???????????????????????????????????????????????????

Answer 4

It's refreshing that you already know as much as you do about tackling this problem, and that you've done some work of your own before asking for help! Very nice.

If your discomfort stems from having all grade point averages (not frequencies) from your data landing in the first two classes, that's a sure sign that you should use narrower frequency classes. You say you've chosen a class width of 1.4/7. Why not try a class width of 1.4/14 instead? Then the class width would be 0.10, and your classes might begin with \[[2.3,2.4), ~[2.4,2.5),~[2.5,2.6),~...\]

Try this out. Hopefully you'll now get data in more than just two classes. If you're still not satified, you could try a class width not of 1.4/ 7, not of 1.4/14, but 1.4/21 or 1.4/28.

Answer 5

thanks for respond mathmale, but if I try 1.4/14-0.1 width
it will be like this
2.3 - 2.4
2.4 - 2.5
2.5 - 2.6
2.6 - 2.7
2.7 - 2.8
2.8 - 2.9
2.9 - 3.0
3.0 - 3.1
3.1 - 3.2
3.2 - 3.4
3.4 - 3.5
3.5 - 3.6
3.6 - 3.7
this will give class boundaries because it is continuous...but
what is about class limit, how can I get them to fill the tally colum

kindly waiting your reply.....

Answer 6

also I knew that to take the class boundary just add 0.5 or 0.05 to the higher limit and subtract 0.5 or 0.05 to lower limit....
how can I apply this rule
i get confuse....

Answer 7

waiting.....

Answer 8

pleeeeeeeeeeeeeeeeeeeeeeease
help help

Answer 9

Hello, SHCTS:

2.3 - 2.4
2.4 - 2.5
2.5 - 2.6
2.6 - 2.7
2.7 - 2.8
2.8 - 2.9
2.9 - 3.0
3.0 - 3.1
3.1 - 3.2
3.2 - 3.4
3.4 - 3.5
3.5 - 3.6
3.6 - 3.7
this will give class boundaries because it is continuous...but
what is about class limit, how can I get them to fill the tally column?

Earlier, I suggested using the following as classes:\[[2.3,2.4), ~[2.4,2.5),~[2.5,2.6),~...\]

Answer 10

These classes are not continuous, as you say they are, because each class begins with the first number, prefaced by "[", and goes up to, BUT DOES NOT INCLUDE, the second number. Example: [2.3,2.4) begins with and includes 2.4, and this subinterval goes up to, but does NOT include, 2.4. So, each class is distinct from every other class. Does this info help?

Answer 11

great ..... it is a new info
but sir ... how can i get class boundaries??????????????????????????????

Answer 12

I'll be with you in a few minutes!

Answer 13

ok ... take your time

Answer 14

the problem statement doesn't specify that you must use class boundaries or class limits, or that you must specify both.

You found the range (1.4), and then (as I'd suggested), divided that by 14. That tells us that the width of each class is 0.1. Can you agree with this much?

If so, then the classes could be as follows:

2.3 to just under 2.4 The data that would fit this class include: 2.35
2.4 to just under 2.5 The data that would fit include: none
2.5 to just under 2.6 The data that would fit this class include: 2.55, 2.56, 2.56, 2.59, 2.50.

Seems to me that this would make a very nice graph with data in several different classes. Please try it.

Answer 15

sorry i didn't write the full question because i was confuse in the first part..
this is the full question

the following data represents the CGPA of students:
2.55 2.86 2.79 2.95 2.56 2.86 2.96 2.56 2.64 2.98 2.35 2.59 2.89 2.95 2.86 2.96 2.91 2.79 2.94 2.86 2.95 2.99 2.5 2.86
3.51 3.08 3.34 3.15 3.37 3.23 3.67 3.35 3.75 3.09 3.40 3.50 3.02 3.43 3.23 3.14 3.18 3.14 3.2 3.04 3.25 3.18 3.28 3.11 3.31 3.04

a-construct a grouped frequency?
b-set up relative frequency distripution
cconstruct histogram, frequency polygon, ogive and stem and leaf plot.

Answer 16

so to do histogram and ogive i will need class boundaries on x axis