Answer:
B. 100
Step-by-step explanation:
(m + n)^2
= m^2 + 2mn + n^2
Rearrange
(m^2 + n^2) + 2mn
Substitute
(68) + 2*16
= 68 + 32
= 100
Answer: 25%
Step-by-step explanation:
Answer:
a) sample size is 40
Step-by-step explanation:
(a)
minutes
Margin of error, E is 75 seconds E=75/60= 1.25 minutes.
The level of significance
for 95% level of significance
For 95% confidence interval
from standard deviation table
Sample size required, n

Rounding off, n=40
Sample size =40
Keywords:
95% confidence, sample size, Wall Street Journal