Question

In a survey, 13 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $30 and standard deviation of $7. Find the margin of error at a 99% confidence level.

Answer 1

Answer:

The margin of error is 5.  

Step-by-step explanation:

Given : In a survey, 13 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $30 and standard deviation of $7.

To Find : The margin of error at a 99% confidence level ?

Solution :

The margin of error formula is given by,

$ME=z\times \frac{\sigma}{\sqrt n}$

We have given,

n=13 , $\sigma=7$

At 99% confidence level the z value is z=2.58

Substitute in the formula,

$ME=2.58\times \frac{7}{\sqrt{13}}$

$ME=2.58\times \frac{7}{3.605}$

$ME=2.58\times 1.941$

$ME=5.00$

Therefore, The margin of error is 5.