In a survey, 28 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $48 and a standard deviation of $6. find the confidence interval at a 90% confidence level.

(a) We are 90% confident that the average (mean) amount that all people spent on their child's last birthday gift, , was between 46.1 dollars and 49.9 dollars. Give your answers rounded to one decimal place.

(b) The sample statistic is dollars.

(c) The margin of error is dollars.

(d) The confidence interval can be written as dollars dollars.