To solve this, let's break down each event with respect to the information given.

1. Sample Space (S): The marbles are numbered from 1 to 8, so the sample space is: $S = \{1, 2, 3, 4, 5, 6, 7, 8\}$

2. Event Definitions:

   • Event $A$: The marble selected has an even number. Thus: $A = \{2, 4, 6, 8\}$
   • Event $B$: The marble selected has a number from 3 to 6. Thus: $B = \{3, 4, 5, 6\}$

3. Calculating Outcomes:

   • (a) Event $A \text{ or } B$: This includes outcomes in either $A$ or $B$ or both. The union of $A$ and $B$ is: $A \cup B = \{2, 3, 4, 5, 6, 8\}$
   • (b) Event $A \text{ and } B$: This includes outcomes that are in both $A$ and $B$. The intersection of $A$ and $B$ is: $A \cap B = \{4, 6\}$
   • (c) The complement of event $B$: This includes outcomes that are in $S$ but not in $B$: $B' = \{1, 2, 7, 8\}$

Final Answers:

• (a) $A \text{ or } B$: $\{2, 3, 4, 5, 6, 8\}$
• (b) $A \text{ and } B$: $\{4, 6\}$
• (c) Complement of $B$: $\{1, 2, 7, 8\}$

Would you like a detailed explanation of any of these steps?

Here are some related questions for further practice:

1. What is the probability of selecting an even-numbered marble from the bag?
2. What is the probability of selecting a marble numbered 3 to 6?
3. How many outcomes are there in the complement of event $A$?
4. If the bag also contained marbles numbered 9 and 10, how would that affect the events?
5. What is the probability of selecting a marble that meets both conditions $A$ and $B$?

Tip: For events involving "or" (union) and "and" (intersection), visualize them with a Venn diagram to better understand overlapping elements.