A coin is tossed two times. The set of outcomes is given as [tex]$S=\{ HH , HT , TH , TT \}$[/tex]. Let [tex]$X$[/tex] represent the number of times heads occurs.

Complete the table.
[tex][tex]$a=$[/tex] \square[/tex]
[tex]$b=$ \square[/tex]
[tex][tex]$c=$[/tex] \square[/tex]

\begin{tabular}{|c|c|}
\hline \multicolumn{2}{|c|}{ Coin Toss } \\
\hline Heads: [tex]$X$[/tex] & Probability: [tex]$P_X(x)$[/tex] \\
\hline 0 & [tex][tex]$a$[/tex][/tex] \\
\hline 1 & [tex]$b$[/tex] \\
\hline 2 & [tex]$c$[/tex] \\
\hline
\end{tabular}



Answer :

Let's solve this problem step-by-step.

First, understand that when a coin is tossed two times, the possible outcomes are [tex]\( S = \{HH, HT, TH, TT\} \)[/tex], where:
- [tex]\( H \)[/tex] represents heads.
- [tex]\( T \)[/tex] represents tails.

Next, we want to find the probabilities for the number of times heads occurs ([tex]\( X \)[/tex]):

1. Number of Heads ([tex]\( X = 0 \)[/tex]):
- Only one outcome has zero heads: [tex]\( TT \)[/tex].
- Probability [tex]\( P_X(0) = a \)[/tex].

2. Number of Heads ([tex]\( X = 1 \)[/tex]):
- Two outcomes have one head: [tex]\( HT \)[/tex] and [tex]\( TH \)[/tex].
- Probability [tex]\( P_X(1) = b \)[/tex].

3. Number of Heads ([tex]\( X = 2 \)[/tex]):
- Only one outcome has two heads: [tex]\( HH \)[/tex].
- Probability [tex]\( P_X(2) = c \)[/tex].

Now let's fill out the probabilities:
1. Total Outcomes: There are 4 possible outcomes (HH, HT, TH, TT).

2. Probability Calculations:
- For [tex]\( X = 0 \)[/tex] (0 heads): There is 1 outcome (TT). The probability is [tex]\( \frac{1}{4} \)[/tex].
- For [tex]\( X = 1 \)[/tex] (1 head): There are 2 outcomes (HT, TH). The probability is [tex]\( \frac{2}{4} = \frac{1}{2} \)[/tex].
- For [tex]\( X = 2 \)[/tex] (2 heads): There is 1 outcome (HH). The probability is [tex]\( \frac{1}{4} \)[/tex].

So:
[tex]\[ a = 0.25 \][/tex]
[tex]\[ b = 0.5 \][/tex]
[tex]\[ c = 0.25 \][/tex]

Completed table:
[tex]\[ \begin{array}{|c|c|} \hline \multicolumn{2}{|c|}{\text{Coin Toss}} \\ \hline \text{Heads: } X & \text{Probability: } P_X(x) \\ \hline 0 & 0.25 \\ \hline 1 & 0.5 \\ \hline 2 & 0.25 \\ \hline \end{array} \][/tex]

To summarize:
- [tex]\( a = 0.25 \)[/tex]
- [tex]\( b = 0.5 \)[/tex]
- [tex]\( c = 0.25 \)[/tex]

DONE