Answer: 0.4667
Step-by-step explanation:
According to 68–95–99.7 rule , About 99.7% of all data values lies with in 3 standard deviations from population mean ().
Here , margin of error = 3s , where s is standard deviation.
As per given , we have want our sample mean to estimate μ μ with an error of no more than 1.4 point in either direction.
If 99.7% of all samples give an within 1.4 , it means that
Divide boths ides by 3 , we get
Hence, So must have 0.4667 as standard deviation so that 99.7 % 99.7% of all samples give an
within 1.4 point of μ .