Answer:
I should use at least 304 students
Step-by-step explanation:
Margin error (E) = t × sd/√n
E = 40
sd = 300
confidence level (C) = 98% = 0.98
significance level = 1 - C = 1 - 0.98 = 0.02 = 2%
t-value corresponding to 2% significance level and infinity degree of freedom is 2.326
n = (t×sd/E)^2 = (2.326×300/40)^2 = 17.445^2 = 304 (to the nearest integer)
He needs $395, cuz he already had $5, and 15×20=300. subtract the 5 from 300.
