Final answer:
The sample size with given standard deviation, error, and confidence level is approximately 69.
Step-by-step explanation:
To determine the sample size, we can use the formula:
sample size = (z-value * standard deviation / margin of error)^2
Given that the standard deviation is 5.28, the margin of error is 1.21, and the confidence level is 0.94, we need to find the corresponding z-value.
Using a standard normal distribution table, we can find that the z-value for a 94% confidence level is approximately 1.88.
Plugging in the values, the sample size is:
sample size = (1.88 * 5.28 / 1.21)^2
sample size ≈ 69.34
Therefore, the sample size is approximately 69.