Question

In a table of random digits, each digit is to occur with a probability of 0.1.

a) A student examines a list of 200 random digits and counts only eleven 4’s and thus claims that the table is not really random. Explain the error in the student’s thinking.
b) How many 7’s would you expect to find in a random digit table consisting of 1000 digits?

Answer 1

@experimentX what about this one? and @FoolAroundMath

Answer 2

(a) possibly that the sample size i.e. a list of 200 is pretty small. If the total number of cases was large say around 10000 times and then the ratio was not near the expected value, then the student would be correct

(b) chance of a 7 is 10% (0.1*100).
So expected number of 7's is 10% of 1000 = 100

Answer 3

Okay thanks so much!
can u help with this one @FoolAroundMath

Answer 4

The chance of a white Christmas (defined as at least one inch of snow on the ground) in Spokane is approximately 60%. Run simulations for each of the following.

a) Run a simulation for 10 years and record how many times a white Christmas occurs. Describe and record your results below.
b) Repeat the above simulation 9 more times. Record your results below.
c) Compare your results with the 60% theoretical probability and comment.

Answer 5

this is the only one which I'm super confused on

Answer 6

did you get the code i sent you earlier?
http://jsfiddle.net/kCdbf/1/

Answer 7

Yea i dont really understand it

Answer 8

..?

Answer 9

http://jsfiddle.net/kCdbf/3/

Answer 10

Sry im Stil not understandin it

Answer 11

it's a computer simulation right?

Answer 12

Its this question on the computer: The chance of a white Christmas (defined as at least one inch of snow on the ground) in Spokane is approximately 60%. Run simulations for each of the following.

a) Run a simulation for 10 years and record how many times a white Christmas occurs. Describe and record your results below.
b) Repeat the above simulation 9 more times. Record your results below.
c) Compare your results with the 60% theoretical probability and comment.

Answer 13

yep!! what do you do on computer simulation?

Answer 14

im not sure?

Answer 15

you write a computer code .. run it, and get results, and write it down.
What do you learn at computer classes? C, QBasic, Pascal??

Answer 16

Okay thanks for your help. but i have never learned computer codes nor have I taken a comuuter class like that

Answer 17

lol ... how do you simulate it then?

Answer 18

Idk.. just not on the computer

Answer 19

So idk what to put

Answer 20

i wrote the code, you take out the result

Answer 21

lol i dont know how to do "codes"

Answer 22

Can u do it for me? and i learn from that

Answer 23

cuz i have never done it before

Answer 24

you didn't open up the link i gave you? did you ... cause i've already written the code up there.

Answer 25

I did

Answer 26

I just dont get the code or what im looking at

Answer 27

what do you get?

Answer 28

I clicked on the link and see writing..... but im not sure what to click next

Answer 29

I put 1 in instead of 0 and hit enter but no new number appeared, it stills ays 60

Answer 30

okay, refresh that page ... and don't click anything!! just show me your screen shot, you should get something like this

Answer 31

that is what it looks like

Answer 32

@experimentX

Answer 33

so now what?

Answer 34

Ha ha ha..

When I opened, it said :

The page at fiddle.jshell.net says :

White Christmas is 6 No white Christmas 4.

Answer 35

Yeah mine said that too

Answer 36

What do I do now

Answer 37

this is your answer for first question.

Answer 38

That is the output it is showing I think..

Answer 39

What is?

Answer 40

damn!! my web developing skills have waned.

Answer 41

a) White christmas: 5
No White Christmas: 5

is that the answer ^?

Answer 42

Is that showing you 5??

Answer 43

Yea, but it changes every time! i dont get it

Answer 44

what do I put for (a)?

Answer 45

You have coded it to generate code randomly.. Right ??

Answer 46

Yes I believe so

Answer 47

yep!! i put up random function

Answer 48

Ok so what do I put for a?

Answer 49

That appears first...

Answer 50

What?

Answer 51

the first one that appeared was 5;5

Answer 52

Your answer is what you are seeing first..

Answer 53

so a) White christmas: 5
No White Christmas: 5

b)

Answer 54

is tht it?

Answer 55

We have given chance of 60%, this will give 50-50 % chances..

Answer 56

So my answer for a is: We have given chance of 60%, this will give 50-50 % chances..

Answer 57

I put a) White christmas: 5
No White Christmas: 5

--> We have given chance of 60 percent, this will give 50-50 percent chances..

Answer 58

Oh My God..

This is what I am saying to X, this is not your answer.. Ha ha ha ha..

Answer 59

yeah you can put up anything!!

Answer 60

Ha ha ha..

Answer 61

Sorry.......

Answer 62

Now put "Anything"..

So, your answer is:

a) Anything..

Ha ha ha..

Answer 63

You're kdidding right

Answer 64

but what do I actually put for a? .

Answer 65

Now you are right..

Answer 66

all you needed as simulation, you simulated and you got answer.

Answer 67

But idk what to put as my answer!

Answer 68

?

Answer 69

If it goes wrong, then X will be responsible..
Ha haha..

Answer 70

(a)

Answer 71

lol ... well, it's just computer question
here is better simulation 10 yrs time, for 9 times
http://jsfiddle.net/kCdbf/4/

Answer 72

So my answer for (a) : (a)
Simulation White Christmas No White Christmas
1 7 3
2 7 3
3 7 3
4 7 3
5 7 3
6 5 5
7 5 5
8 9 1
9 3 7
10 6 4

Answer 73

Choose one of them..

Answer 74

so (a)
Simulation White Christmas No White Christmas
1 7 3

Answer 75

thats it?

Answer 76

You are expert in copying and pasting..

Answer 77

Oh My God!!

Answer 78

yep!!
http://jsfiddle.net/kCdbf/5/

Answer 79

Why oh my god?

Answer 80

Nothing, it is difficult for me to explain it to you..

Answer 81

um ok

Answer 82

can u guys just tell me.... for a, you said only one of them ,... so i got:

Answer 83

would this be right:: (a)
Simulation White Christmas No White Christmas
1 7 3

Answer 84

Best of Luck @experimentX

Ha ha ha..

Answer 85

and then (b) would be all of them? Simulation White Christmas No White Christmas
1 7 3
2 7 3
3 7 3
4 7 3
5 7 3
6 5 5
7 5 5
8 9 1
9 3 7
10 6 4

Answer 86

I thought you were supposed to be nice and helpful on open study @waterineyes

Answer 87

lol ... he is nice, I'm extra nice, since i haven't done this stuff once in a while.
next time don't expect me to so nice :P

Answer 88

Sorry, I am leaving, that is why I have said those words...

And those are for ExperimentX..

Answer 89

@waterineyes bye

Answer 90

thanks @experimentX

Answer 91

don't put that simulation number, just put the white christmas

Answer 92

Sorry, I have not clearly mentioned, I am leaving this post, not openstudy..

Ha ha ha..

And sorry @schmidtdancer if I have hurt your feelings..

Answer 93

Youre saying that for (a)? Instead of writing the numbers, I just put: white christmas: 5, not white christmas: 5

Answer 94

Looks nice now..