If the table below represents a probability model based on observed frequencies, what is the value of x ?

This table shows a probability model for the letters Y, C, A, R, E, and S based on observed frequencies.
Y C A R E S
P(Y) 0.25 0.18 0.30 0.17 x (1 point)
Responses

0.20
0.20

0.10
0.10

1
1

0.01
0.01
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1 answer

In a probability model, the sum of all the probabilities must equal 1. From the table provided, we have the following probabilities:

  • P(Y) = 0.25
  • P(C) = 0.18
  • P(A) = 0.30
  • P(R) = 0.17
  • P(E) = x
  • P(S) is not given, but we can assume it follows the same pattern as the others.

To solve for x, we can sum the known probabilities and set the equation as follows:

\[ P(Y) + P(C) + P(A) + P(R) + P(E) + P(S) = 1 \]

Given that the probabilities of Y, C, A, and R are:

\[ 0.25 + 0.18 + 0.30 + 0.17 + x + P(S) = 1 \]

Calculating the known sums:

\[ 0.25 + 0.18 + 0.30 + 0.17 = 0.90 \]

Now, our equation simplifies to:

\[ 0.90 + x + P(S) = 1 \]

Now, we need to find the value of \( x \) and make an assumption about \( P(S) \). If we assume \( P(S) = 0 \) (or simply that \( S \) is not happening), we can solve for \( x \):

\[ 0.90 + x = 1 \] \[ x = 1 - 0.90 = 0.10 \]

Thus, the value of \( x \) is 0.10.