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
Answer:
Statement 4 is incorrect.
Step-by-step explanation:
#4 is incorrect. This statement is assuming that both 3x+5 and 4x are equal, but the correct way to use them and achieve 180 (definition of supplementary) degrees is by writing it as: 3x+5 + 4x = 180. (I spaced the 3x+5 and 4x to make it clear that these are two angles added together.) With this equation, you will be able to find the x and the substitute it back in to complete the equation.
Step-by-step explanation:
(3x+5)-(4x²-2)-(x²-3x+1)
= 3x+5-4x²+2-x²+3x-1
=6x+6-5x²
=-5x²+6x+6