The electric bills of a sample of 31 households provided a mean of $119 with a sample standard deviation of $11. The population standard deviation is unknown.

Let us provide a 95% confidence interval estimate of the mean electric bill for the population of US households. We will assume this population to be normally distributed.

What will the margin of error be for the 95% confidence interval?

ROUND TO TWO DECIMAL PLACES

Hint: you'll need to find the critical value for tusing a t-table(Links to an external site.)

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