For a confidence level of 95% with a sample size of 25, find the critical t value.

In a survey, 27 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $39 and standard deviation of $5. Find the margin of error at a 80% confidence level. Give your answer to two decimal places.

We wish to estimate what percent of adult residents in a certain county are parents. Out of 300 adult residents sampled, 51 had kids. Based on this, construct a 99% confidence interval for the proportion, p, of adult residents who are parents in this county. Give your answers as decimals, to three places. _____________ < p <_____________