Is there a way to approach this problem in Excel:

The Marriott Hotel marketing team wants to estimate , the proportion of the hotel guests who were return visitors in the past three years. They select a simple random sample of 150 guests from the past three year's records and finds that 27 of the sampled guests are return visitors.

1. Compute a point estimate for .
2. What are the upper and lower bounds for the 90% confidence interval for (4 decimals)?