The confidence interval in the interval form can be expressed as [LL, UL], where LL is the lower limit of the confidence interval and UL is the upper limit.
To solve this question, follow the steps below.
Step 01: Transform the numbers into decimals.
42% = 42/100 = 0.42
8% = 8/100 = 0.08
Then, the confidence interval is 0.42 ± 0.08
Step 02: Find the lower limit (LL).
The lower limit is 0.42 - 0.08, which is 0.34.
Step 03: Find the upper limit (UP).
The upper limit is 0.42 + 0.08, which is 0.50.
Step 04: Write the confidence interval in interval form.
Answer: [0.34, 0.50].