You want to estimate the average weight in tons of loads carried by trucks through a particular stretch of road. From previous information the standard deviation is expected to be σ =21.35 tons. How...

You want to estimate the average weight in tons of loads carried by trucks through a particular stretch of road. From previous information the standard deviation is expected to beσ=21.35   tons. How many trucks must be weighed to estimate the the tons per truck to within 4 tons at a 95% level of confidence. Round your answer up to the largest whole number.