cherylim23's methods question thread :)

[|ll|lll|]

The relation: , can be changed to a function by restricting the:
A domain to [-3, 0]
B domain to [-6, -3]
C range to [-3, 3]
D range to [-3, 0]
E domain to [-3, 0] and range to [-3, 3]

I think there's a problem with this questions, but anyway, the answer is apparently D.

This is a really simple question.
The chalk box of a teacher contains 8 white sticks of chalk, 3 yellow sticks and 2 blue sticks. If each stick has an equal chance of being selected, the probability the teacher randomly selects a yellow stick is:
A 0.2
B 0.25
C 0.3
D 0.33
E 0.4

My answer is which I'm positively sure it's right. Correct answer is A eh? D:

Edit: How do get rid of the HTML code btw?

[m@tty]

is a circle of radius 3 and center .

A function means that there is only one y-value for all x-values. If you split the circle at you are left with two functions. Each of domain and range of either or . Therefore D is correct.

[|ll|lll|]

I thought C, D and E are all possible answers.

Edit: Oops, definitely not E. Because it'll be a one-to-many relation.
Looking at this thread, I seem to ask a lot of circle questions hahah

[m@tty]

I'm not sure if restricting the range to is even feasible, lol. The original range is ...

[m@tty]

For the numbers you have given the Pr is indeed 3/13. If the answer is meant to be A I assume that there was meant to two more sticks of chalk between white and blue.

[|ll|lll|]

Some questions~~

16.    The equivalent in degrees of 0.25 radians is
A.  14.32     B.  57.29  C.  90   D.  180   E.  none of these

Answer is A but shouldn't it be ? -confused-

In Victoria, one of two daily morning newspapers claims that 85% of households that subscribe to the newspaper have their papers delivered each morning before 7.30am. In a random sample of 50 households that subscribe to this daily newspaper, the probability that exactly 45 receive their paper before 7.30am is given by
A.
B.
C.
D.
E.

22. The probability of a soccer team scoring a goal from a penalty shot is 0.78.
During a particular game the team is awarded four penalty shots. The probability that they score three goals from these penalty shots is closest to:
A. 0.1044
B. 0.3702
C. 0.4176
D. 0.4746
E. 0.7878

All help is appreciated!

[98.40_for_sure]

For your 1st question:
Conversion from radians to degrees is x180 then /pi
Thus (0.25 x 180)/pi = 14.32

For your 2nd question:
Let X be the number of households that receive their paper before 7:30am
X~Bi(n=50,p=0.85)
So by formula
Pr(X=45) = nCr(50,45) x (0.85)^45 x (0.15)^5
Thus, C

For your 3rd question:
Let Y be the number of goals scored from penalty shots
Y~Bi(n=4,p=0.78)
Pr(Y=3) = nCr(4,3) x (0.78)^3 x (0.22)^1
           = 0.4176
Thus, C

[|ll|lll|]

Thanks!

However, I don't get your notation for: X~Bi(n=50,p=0.85) and Y~Bi(n=4,p=0.78).

And is 0.25 radian = ?

[Blakhitman]

Some questions~~

16.    The equivalent in degrees of 0.25 radians is
A.  14.32     B.  57.29  C.  90   D.  180   E.  none of these

Answer is A but shouldn't it be ? -confused-

to convert to degrees multiply by

In Victoria, one of two daily morning newspapers claims that 85% of households that subscribe to the newspaper have their papers delivered each morning before 7.30am. In a random sample of 50 households that subscribe to this daily newspaper, the probability that exactly 45 receive their paper before 7.30am is given by
A.
B.
C.
D.
E.

X~Bi(50,0.85) and we know
so in this case so D

22. The probability of a soccer team scoring a goal from a penalty shot is 0.78.
During a particular game the team is awarded four penalty shots. The probability that they score three goals from these penalty shots is closest to:
A. 0.1044
B. 0.3702
C. 0.4176
D. 0.4746
E. 0.7878

Again, X~Bi(4,0.78) so to find

All help is appreciated!

[98.40_for_sure]

Thanks!

However, I don't get your notation for: X~Bi(n=50,p=0.85) and Y~Bi(n=4,p=0.78).

And is 0.25 radian = ?

Well it just says X is a binomial distribution, where the number of trials is 50, and the probability is 0.85.

No you're confusing a radian with pi. A radian is 180/pi. It's 50something degrees roughly

[Blakhitman]

Nope, but if this was CAS active then you would naturally use binompdf on your CAS (for the last question in this case).

[98.40_for_sure]

You could always list out all the possible combinations
there are... 2118760 of them

[TyErd]

how would you do this one.

[fady_22]

Pr(odd)=0.3+0.25=0.55

Let O~Bi(5,0.55)
Pr(O>=3)=Pr(O=3)+Pr(O=4)+P(O=5)
You should get E.

[TyErd]

okay thanks very much