900 secondary school students are selected randomly from across the country because they have achieved 10 GCSEs at grade A -C.There is a standard deviation of 0.4.Assuming a 95% confidence rate,what is the margin of error?
A)0.011
B)0.025
C)0.178
D)0.555

Question

Quizplus · Accepted Answer

The margin of error is calculated using the formula: Margin of Error = Z * (σ/√n). For a 95% confidence level, the Z-score is approximately 1.96. Given σ = 0.4 and n = 900, the margin of error is 1.96 * (0.4/√900) = 0.025.

900 Secondary School Students Are Selected Randomly from Across the Country