Since we know the population standard deviation and the
sample size is more than 30, therefore we use the z statistic test. The formula
for calculating the z score is given as:
At 98% confidence level, the value of z is:
z = 2.33
Now we can calculate for the margin of error (MOE) using
the formula:
MOE = z * σ / sqrt (n)
where,
σ = standard deviation = 4 hours
n = sample size = 200
Substituting the given values:
MOE = 2.33 * 4 / sqrt (200)
MOE = 0.66
Therefore the margin of error for 98% confidence level is
0.66
