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Standardized tests for certain subjects, given to high school students, are scored on a scale of 1 to 5. Let [tex]X[/tex] represent the score on a randomly selected exam. The distribution of scores for one subject's standardized test is given in the table.

\begin{tabular}{|c|c|c|c|c|c|}
\hline
Score & 1 & 2 & 3 & 4 & 5 \\
\hline
Probability & 0.18 & 0.20 & 0.26 & 0.21 & 0.15 \\
\hline
\end{tabular}

What is the probability of earning a score of 3 or higher?
A. 0.26
B. 0.36
C. 0.62
D. 0.66


Sagot :

Let's analyze the given data carefully to determine the probability of earning a score of 3 or higher on the standardized test.

The provided table shows the scores and their corresponding probabilities:

[tex]\[ \begin{array}{|c|c|} \hline \text{Score} & \text{Probability} \\ \hline 1 & 0.18 \\ 2 & 0.20 \\ 3 & 0.26 \\ 4 & 0.21 \\ 5 & 0.15 \\ \hline \end{array} \][/tex]

We need to find the probability of earning a score of 3 or higher. This means we need to consider the scores 3, 4, and 5.

To solve this, we add the probabilities of these scores:

[tex]\[ \begin{aligned} \text{Probability of scoring 3} &= 0.26 \\ \text{Probability of scoring 4} &= 0.21 \\ \text{Probability of scoring 5} &= 0.15 \\ \end{aligned} \][/tex]

Next, we sum these probabilities:

[tex]\[ 0.26 + 0.21 + 0.15 = 0.62 \][/tex]

Therefore, the probability of earning a score of 3 or higher is [tex]\(0.62\)[/tex].

The correct answer is: 0.62