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# Histogram S1 watch

1. Can someone explain this to me? I did FD= F/CW and am wrong. Any ideas?

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2. (Original post by AJA1994)
Can someone explain this to me? I did FD= F/CW and am wrong. Any ideas?
Can you please give more detail?

Is this 7a? Did you draw a histogram and it was different to the solution? Where is your attempt? Why did you post 3 pictures showing the same thing?
3. (Original post by notnek)
Can you please give more detail?

Is this 7a? Did you draw a histogram and it was different to the solution? Where is your attempt? Why did you post 3 pictures showing the same thing?
It wasn't deliberate. I kept uploading pics and it said failed so I tried to re upload and then this happened. So it's a mistake. Yes 7a) my attempt was a histogram with FD values of 5,10,4,110,75 and 1.6. I used the FD=f/cw
4. (Original post by AJA1994)
It wasn't deliberate. I kept uploading pics and it said failed so I tried to re upload and then this happened. So it's a mistake. Yes 7a) my attempt was a histogram with FD values of 5,10,4,110,75 and 1.6. I used the FD=f/cw
The solution looks wrong to me.

Looking at the table, the 18-18.5 class clearly has a bigger density than the 18.5-20 class.
5. (Original post by notnek)
The solution looks wrong to me.

Looking at the table, the 18-18.5 class clearly has a bigger density than the 18.5-20 class.
That's what I thought but the back of the book has the same solution too so it's really thrown me. I thought perhaps I wasn't considering the K value. Trouble is I don't know when to assume the k value isn't 1?
6. (Original post by AJA1994)
That's what I thought but the back of the book has the same solution too so it's really thrown me. I thought perhaps I wasn't considering the K value. Trouble is I don't know when to assume the k value isn't 1?
I considered this but whatever the scaling, the 18-18.5 group has a bigger density than the 18.5-20 class so it has to be a mistake.
7. (Original post by notnek)
I considered this but whatever the scaling, the 18-18.5 group has a bigger density than the 18.5-20 class so it has to be a mistake.
Could you explain the k constant please? Also how would I know when it isn't 1?
8. I can see a couple of things wrong with this "histogram". First, the vertical scale is marked 0 / 25 / 30 / 35 etc. On a linear scale, the first value should be 20 not 0 (or 0 is correct and the rest of it is wrong). Second, if we ignore the vertical scale markings and just think of the vertical scale graduated in "small squares", it looks as though frequency (not frequency density) has been plotted, with one unit of frequency mapped to one square vertically.
9. (Original post by old_engineer)
I can see a couple of things wrong with this "histogram". First, the vertical scale is marked 0 / 25 / 30 / 35 etc. On a linear scale, the first value should be 20 not 0 (or 0 is correct and the rest of it is wrong). Second, if we ignore the vertical scale markings and just think of the vertical scale graduated in "small squares", it looks as though frequency (not frequency density) has been plotted, with one unit of frequency mapped to one square vertically.
Good spot. That's a pretty bad error for a Solutionbank.
10. FD = k times x. Make sure you have accounted for a constant as this is really important.
11. (Original post by Anfanny)
FD = k times x. Make sure you have accounted for a constant as this is really important.
What is x?
12. Well that should be class width.
13. (Original post by Anfanny)
FD = k times x. Make sure you have accounted for a constant as this is really important.
How would I know when k is not 1?
14. (Original post by notnek)
Good spot. That's a pretty bad error for a Solutionbank.
It's the back of book answer also so I was sure maybe I was wrong. Couldn't imagine both were wrong
15. (Original post by AJA1994)
Could you explain the k constant please? Also how would I know when it isn't 1?
I haven't done S1 in a while so I won't be able to tell you when you should be using / expecting to see scaling in a histogram.

Hopefully someone who is doing/teaching S1 now can help?

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