Question

Calculate the margin of error

Answer 1

Answer:

The margin of error is 3.465

Step-by-step explanation:

Margin of error = t × sd/√n

n = 92, degree of freedom = n - 1 = 92 - 1 = 91, t-value corresponding to 91 degrees of freedom and 90% confidence level is 1.6618, sd = 20

Margin of error = 1.6618×20/√92 = 33.236/9.592 = 3.465

Answer 2

Answer:

The margin of error is of 3.43.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.9}{2} = 0.05$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$.

So it is z with a pvalue of $1-0.05 = 0.95$, so $z = 1.645$

Now, find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

So

$M = 1.645*\frac{20}{\sqrt{92}} = 3.43$

The margin of error is of 3.43.