We are requested to estimate the mean concentration of the 222Ra gas near a uranium treatment plant for the month of July. A total of 10 measurements 1x , 1x ,… 1x were taken during the month of July 2011. Each measurement represents a duration of 24 hours and started at 6h00AM. The 10 days for which the sampling took place were selected randomly among the 31 days of the month. The measurements are listed below:
1450, 1510, 1480, 1680, 2130, 2110, 1010, 1290, 1150 and 1300 (units of pCi/day).
Provide an estimate of the mean concentration of the 222Ra gas near the plant and the standard deviation of the mean for the month of July.