Question

Which intervals can you use to make a frequency table for the data set?

95 103 110 86 72 77 97 118 83 101 105 79 78 95 93

Answer 1

A. 70–89, 90–99, 100–109, 110–119


B. 70–85, 85–100, 100–115, 115–130


C. 70–84, 85–99, 100–114, 115–129


D. 70–89, 90–104, 105–115, 116–125

Answer 2

@jim_thompson5910

Answer 3

@sourwing

Answer 4

hint: the class width must be the same

http://tistats.com/definitions/class-width/

Answer 5

Can you walk me through this? I am completely new to this Topic @jim_thompson5910

Answer 6

Did you see that link?

Answer 7

Still looking at it... although maybe you can help me understand some of what they are saying?

Answer 8

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Answer 9

notice how in their example they start at 151 and the next interval starts at 201

so the class width is 201 - 151 = 50

Answer 10

basically in that example, the start of each interval is increasing by 50 (same with the end)

Answer 11

Class width has to be the same with every one?

Answer 12

Ok, I am going to put them in order. Will that help?

Answer 13

and it says

"The following are examples of a class width.

Difference between two consecutive lower class limits
Difference between two consecutive upper class limits
"

Answer 14

yeah you should sort first

Answer 15

Ok, 1 sec please

Answer 16

72,77,78,79,83,86,93,95,95,97,101,103,105,110,118

Answer 17

Did I miss anything?

Answer 18

Nope, I didn't. Ok. Looks like about about 1-10 gap between each?

Answer 19

What's the min?
What's the max?

Answer 20

Sorry, Min is 71 Max is 118? @jim_thompson5910

Answer 21

how are you getting 71?

Answer 22

Min is 72?

Answer 23

yes

Answer 24

so 70 is a nice round starting point

Answer 25

so that explains why they all start with 70

Answer 26

what is the class width of choice A?

Answer 27

Umm

Answer 28

20 space for the first, than 10 for the rest

Answer 29

Am I wrong @jim_thompson5910

Answer 30

70–89, 90–99, 100–109, 110–119


70 to 90 is a jump of 20

90 to 100 is a jump of 10

So we can see here that the class width is NOT the same from interval to interval

The class widths must be the same

Answer 31

So that's why choice A is wrong

Answer 32

Ok

Answer 33

B is a constant jump of 15. Is that right?

Answer 34

That is correct, but there's a flaw in choice B

Answer 35

Can you spot it?

Answer 36

Let me try

Answer 37

It jumps too much?

Answer 38

I think it is C....

B jumps too much
D Is not consistent in it's jumping

Answer 39

@jim_thompson5910

Answer 40

Here's why there's a flaw in B

Let's say you had the number 85

Which interval does 85 go in? Does it go in 70–85? or does it go in 85–100?

It cannot go in both and there's no way to tell which 85 is exclusive or inclusive

So this overlap is the flaw with B

Answer 41

D is wrong for similar reasons of why A is wrong, so you are correct in eliminating D

Answer 42

So C is correct?

Answer 43

yes it is

Answer 44

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Answer 45

Not that it can repay you in anyway

Answer 46

you're welcome and don't worry about that sort of thing