Answer: Option 'd' is correct.
Step-by-step explanation:
Since we have given that
Margin of error = 0.5 years
Standard deviation = 5
At 90% confidence, z = 1.645
We need to find the minimum size of the sample they must take.
So,

Hence, Option 'd' is correct.
Answer: If you are using a calculator, simply enter 64÷320×100 which will give you 20 as the answer.
Step-by-step explanation: Hope it helps:)
and tryna mark a child brainlest ;)
Answer:
I'm not sure if this will be able to help, though I found the same question, but answered by someone who is far more advanced with this, and has answered for more questions than I have. Hope this can help, if not please comment, so I can delete.
brainly.com/question/21188240