If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Calculating a t interval for a mean

You might need: Calculator,t table


An economist studying fuel costs wants to estimate the mean price of gasoline in her state on a certain day. On that day, she takes an
of 12 gas stations and finds the sample mean price (in dollars per gallon) is x¯=$2.29 with a standard deviation of sx=$0.20. The prices in the sample are roughly symmetric with no distinct outliers.
Based on this sample, which of the following is closest to a 90% confidence interval for the mean price of gasoline that day in her state?
صرف 1 جواب چنو