Answer:
(a) The estimate the percentage of US adults who were victims at the 90% confidence level is (12%, 15%).
(b) The estimate the percentage of US adults who were victims at the 99% confidence level is (11%, 16%).
Step-by-step explanation:
The percentage of Americans who had been victims of crime during a one-year period is,
.
The sample selected was of size, n = 1105.
The (1 - α)% confidence interval for the population proportion is:

(a)
The confidence level is 90%.
The critical value of z for 90% confidence level is, z = 1.645.
Compute the 90% confidence interval for the percentage of US adults who were victims as follows:


Thus, the estimate the percentage of US adults who were victims at the 90% confidence level is (12%, 15%).
(b)
The confidence level is 99%.
The critical value of z for 99% confidence level is, z = 2.58.
Compute the 99% confidence interval for the percentage of US adults who were victims as follows:


Thus, the estimate the percentage of US adults who were victims at the 99% confidence level is (11%, 16%).