2. A researcher wishes to estimate the mean weekly wage of several thousands of workers employed in a plant within plus or minus $20 and with 90% degree of confidence. From past experience, the researcher knows the weekly wages of these workers are normally distributed with a standard deviation of $40. What is the minimum sample size required.

an advantage of the standard deviation is that it increases as the dispersion of the data increases. e. the interquartile range is preferred when the data are not skewed or no have outliers. an advantage of the standard deviation is that it uses all the observations in its computation.

she was supposed to add the hours(38.5) and multiply the amount of money she earned(7.50) resulting in $288.75 .

correct me if i'm wrong and if it is i'm truly sorry.