Suppose that the amount of money spent per week on groceries is normally distributed with an unknown mean and standard deviation. A random sample of 20 grocery bills is taken and gives a sample mean of $79 and a sample standard deviation of $13.

df...1819202122t0.10...1.3301.3281.3251.3231.321t0.05...1.7341.7291.7251.7211.717t0.025...2.1012.0932.0862.0802.074t0.01...2.5522.5392.5282.5182.508t0.005...2.8782.8612.8452.8312.819

Find the margin of error for a95% confidence interval estimate for the population mean using the Student's t-distribution.

• Use the portion of the table above. Round the final answer to two decimal places.