2017-08-30

Aug 30 In-Class Exercise Thread.

Hi Everyone,
Post your solutions to the Aug 30 In-class exercise in this thread.
Best, Chris
Hi Everyone, Post your solutions to the Aug 30 In-class exercise in this thread. Best, Chris

-- Aug 30 In-Class Exercise Thread
My birthday is August 1.
State Space:
  • `S={Heads, Tails}`
Random Variable:
  • `X[Heads] = 5`
  • `X[Tails] = 1`
Probability Distribution:
  • `Pr[Heads] = 1/1 = 1`
  • `Pr[Tails] = 1 - Pr[Heads] = 0`
Expected Value:
  • `E[X] = 5*Pr[Heads] + 1*Pr[Tails] = 5*1 + 1*0 = $5`
(Edited: 2017-08-30)
My birthday is August 1. '''State Space:''' * @BT@S={Heads, Tails}@BT@ '''Random Variable: ''' * @BT@X[Heads] = 5@BT@ * @BT@X[Tails] = 1@BT@ '''Probability Distribution:''' * @BT@Pr[Heads] = 1/1 = 1@BT@ * @BT@Pr[Tails] = 1 - Pr[Heads] = 0@BT@ '''Expected Value:''' * @BT@E[X] = 5*Pr[Heads] + 1*Pr[Tails] = 5*1 + 1*0 = $5@BT@

-- Aug 30 In-Class Exercise Thread
  • X = Amount Bob pays
  • `P(X=5) = p(H) = 1/7`
  • `P (X=1) = P(T) = 6/7`
  • Expected value = `5*(1/7) + 1*(6/7) = 1.57`
(Edited: 2017-08-30)
*X = Amount Bob pays * @BT@P(X=5) = p(H) = 1/7@BT@ * @BT@P (X=1) = P(T) = 6/7@BT@ *Expected value = @BT@5*(1/7) + 1*(6/7) = 1.57@BT@

-- Aug 30 In-Class Exercise Thread
Birthdate is 4th.
Pr(pay=5) = 1/4, Pr(pay=1) = 3/4. Therefore, expected value = 5/4 + 3/4 = 2
Birthdate is 4th. Pr(pay=5) = 1/4, Pr(pay=1) = 3/4. Therefore, expected value = 5/4 + 3/4 = 2

-- Aug 30 In-Class Exercise Thread
  • S = {head, tail}
  • P(head) = 1/8
  • P(tail) = 7/8
  • randomV(head) = 5
  • randomV(tail) = 1
  • payment = sum(P*randomV) payment = 1/8 *5 + 7/8 *1 = $1.5
(Edited: 2017-08-30)
*S = {head, tail} *P(head) = 1/8 *P(tail) = 7/8 *randomV(head) = 5 *randomV(tail) = 1 *payment = sum(P*randomV) payment = 1/8 *5 + 7/8 *1 = $1.5

-- Aug 30 In-Class Exercise Thread
  • 'X= total money received from Bob.'
  • P(Heads)=1/26
  • P(Tails)=25/26
  • Xh=5
  • Xt=1
  • The expected amount to receive from Bob
  • E[X]= Xh * p(Heads) + Xt * p(Tails)
  • E[X]=5*1/26 + 25/26
  • E[X]=30/26=15/13
  • E[X]=$1.15
(Edited: 2017-08-30)
*'X= total money received from Bob.' *P(Heads)=1/26 *P(Tails)=25/26 *Xh=5 *Xt=1 *The expected amount to receive from Bob *E[X]= Xh * p(Heads) + Xt * p(Tails) *E[X]=5*1/26 + 25/26 *E[X]=30/26=15/13 *E[X]=$1.15

-- Aug 30 In-Class Exercise Thread
My Birthday is on 24.
So, P(H) = 1/24
P(T) = 23/24
Let X be the random variable corresponding to the money Bob pays. Then, by the given statement:
X = {5, 1}
P(X=5) = P(H) = 1/24
P(X=1) = P(T) = 23/24
E[X] = 5*P(X=5) + 1*P(X=1)
	= 5/24 + 23/24
	= 28/24
Thus, expected value is $1.67
(Edited: 2017-08-30)
My Birthday is on 24. So, P(H) = 1/24 P(T) = 23/24 Let X be the random variable corresponding to the money Bob pays. Then, by the given statement: X = {5, 1} P(X=5) = P(H) = 1/24 P(X=1) = P(T) = 23/24 E[X] = 5*P(X=5) + 1*P(X=1) = 5/24 + 23/24 = 28/24 Thus, expected value is $1.67

-- Aug 30 In-Class Exercise Thread
Birthday : 20
S:{heads, tails} Pr_Head=1/20 Pr_Tail=1-Pr_Head Pr_Tail=19/20 Val=5*(Pr_Head)+1*(Pr_Tail) Val=5*1/20+19/20 Val=1.35
Birthday : 20 S:{heads, tails} Pr_Head=1/20 Pr_Tail=1-Pr_Head Pr_Tail=19/20 Val=5*(Pr_Head)+1*(Pr_Tail) Val=5*1/20+19/20 Val=1.35

-- Aug 30 In-Class Exercise Thread
  • Birthday = July 4
  • Random Variable X
  • Sample Space: H, T
  • X[Head] = $5
  • X[Tail] = $1
Probability Distribution:
  • P(H) = 0.25
  • P(T) = 0.75
Expected Value:
  • E(X) = $5 * 0.25 + $1 * 0.75 = $2
(Edited: 2017-08-30)
*Birthday = July 4 *Random Variable X *Sample Space: H, T * X[Head] = $5 * X[Tail] = $1 Probability Distribution: *P(H) = 0.25 *P(T) = 0.75 Expected Value: *E(X) = $5 * 0.25 + $1 * 0.75 = $2

-- Aug 30 In-Class Exercise Thread
birth date=13
p(H)= 1/13
p(T)= 12/13
E[x]= 5*1/13+1*12/13 = 17/13= $1.307
(Edited: 2017-08-30)
birth date=13 p(H)= 1/13 p(T)= 12/13 E[x]= 5*1/13+1*12/13 = 17/13= $1.307
[ Next ]
X