題組內容

4. (30%) This was a survey about the revisit intention of a shopping website in Jan. 2021. We knew that visitors aged 21 to 30 were 3000 persons, aged 31 to 40 were 1500 persons and aged 41 to 50 were 500 persons. Therefore, this survey randomly sampled 300 persons from visitors aged 21 to 30, 150 persons from visitors aged 31 to 40, 50 persons from visitors aged 41 to 50 respectively.

(b) Follow (a), calculate the 95% confidence interval for the probability.