Question

Data collected by an arcade store manager yielded the following confidence interval for the proportion of customers who played the new video game the store just bought: (21% to 30%). Give the margin of error in percentage points

Answer 1

Solution :

Given that,

Upper confidence interval = 30% = 0.30

Lower confidence interval = 21% = 0.21

Point estimate = = (Upper confidence interval + Lower confidence interval ) / 2

= (0.30 + 0.21) / 2

= 0.51 / 2

                            = 0.255

= 0.255

Margin of error = E = Upper confidence interval -

                           = 0.300 - 0.255

                          = 0.045

Margin of error = E = 4.5%