To find the margin of error (M.E.), we need to use the formula:
M.E. = z * (σ / √n)
Where:
z is the critical value for the desired confidence level,
σ is the standard deviation, and
n is the sample size.
For a confidence level of 99.5%, the critical value can be approximated as 2.807 (rounded to 3 decimal places).
Plugging in the values:
M.E. = 2.807 * (13.8 / √7)
Calculating this, the margin of error (M.E.) is approximately 16.6 (rounded to one decimal place).
Therefore, the margin of error (M.E.) is 16.6.