Answer:
Either A or B
Step-by-step explanation:
Its not C or D sorry I couldn't be much help, but I hope that makes it a bit easier?
It’s a frequency table, you find the middle number from the prices of mail received and you would multiply it. Not sure what with but if you search on Google Frequency tables there should be a good explanation.
Hope this helped you!
Answer:
a. [ 0.454,0.51]
b. 599.472 ~ 600
Step-by-step explanation:
a)
Confidence Interval For Proportion
CI = p ± Z a/2 Sqrt(p*(1-p)/n)))
x = Mean
n = Sample Size
a = 1 - (Confidence Level/100)
Za/2 = Z-table value
CI = Confidence Interval
Mean(x)=410
Sample Size(n)=850
Sample proportion = x/n =0.482
Confidence Interval = [ 0.482 ±Z a/2 ( Sqrt ( 0.482*0.518) /850)]
= [ 0.482 - 1.645* Sqrt(0) , 0.482 + 1.65* Sqrt(0) ]
= [ 0.454,0.51]
b)
Compute Sample Size ( n ) = n=(Z/E)^2*p*(1-p)
Z a/2 at 0.05 is = 1.96
Samle Proportion = 0.482
ME = 0.04
n = ( 1.96 / 0.04 )^2 * 0.482*0.518
= 599.472 ~ 600
