For margin of error to be a maximum of 3:
3 = z*(SD / sqrt(n)), where z is the z-score, SD is the standard deviation and n is the sample size.
z = 1.96 for a 95% confidence interval, and we are given SD = 15.
3 = 1.96*15/sqrt(n)
sqrt(n) = 9.8
n = 96.04 ~ 96 commercials.
Step-by-step explanation:
Hey there!
Please look your required answer in pictures.
<u>Hope</u><u> it</u><u> helps</u><u>!</u>
One answer is 6/10 ths; i hope this helps (;