You get an answer to your question really quick,
...like now!
Answer:
4/20 - 5/20 = -1/20, and therefore, since the answer is negative, you've proven that 5/20 (or the original 1/4) is actually the bigger number, not the 4/20 (or 1/5).
Step-by-step explanation:
Answer: a) 0.84 b) 0.67 c) 1.28
Step-by-step explanation:
Using the standard normal distribution table for z-value , we have
(a) The value of
would result in a 80% one-sided confidence interval : 
(b) The value of
would result in a 85% one-sided confidence interval : 
(c) The value of
would result in a 90% one-sided confidence interval : 