Consumer confidence an increase in the rate of consumer savings is frequently tied to a lack of confidence in the economy and is said to be an indicator of a recessional tendency in the economy. a random sampling of n = 200 savings accounts in a local community showed a mean increase in savings account values of 7.2% over the past 12 months, with a standard deviation of 5.6%. estimate the mean percent increase in savings account values over the past 12 months for depositors in the community. find the margin of error for your estimate.