To find the probability of "Not a 1", we need to look at the total probability and the probability of getting 1. Here are the steps involved:
1. Identify the given probabilities:
- \( P(X = 1) = 0.30 \)
- \( P(X = 2) = 0.40 \)
- \( P(X = 3) = 0.15 \)
- \( P(X = 4) = 0.15 \)
2. Calculate the probability of "Not a 1":
- The probability of an event not happening is equal to 1 minus the probability of the event happening.
[tex]\[
P(\text{Not a 1}) = 1 - P(X = 1)
\][/tex]
3. Substitute the given probability into the formula:
[tex]\[
P(\text{Not a 1}) = 1 - 0.30
\][/tex]
4. Perform the subtraction:
[tex]\[
P(\text{Not a 1}) = 0.70
\][/tex]
Therefore, the probability of "Not a 1" is \(0.70\).
The answer is [tex]\(\boxed{0.70}\)[/tex], which corresponds to option C in the provided choices.
