Answer:
The sample size needed is 2401.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
The margin of error of the interval is:

95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
Estimate the sample size needed if no estimate of p is available so that the confidence interval will have a margin of error of 0.02.
We have to find n, for which M = 0.02.
There is no estimate of p available, so we use 






The sample size needed is 2401.
To convert decimal over to percent, we move the decimal place two places to the right. So 0.5 becomes 50%.
Answer:
-1
Explanation:
X - 9 = -10
+9 +9
——————
X = -1
Answer:
(a) 
The expected number in the sample that treats hazardous waste on-site is 0.383.
(b) 
There is a 0.000169 probability that 4 of the 10 selected facilities treat hazardous waste on-site.
Step-by-step explanation:
Professional Geographer (Feb. 2000) reported the hazardous waste generation and disposal characteristics of 209 facilities.
N = 209
Only eight of these facilities treated hazardous waste on-site.
r = 8
a. In a random sample of 10 of the 209 facilities, what is the expected number in the sample that treats hazardous waste on-site?
n = 10
The expected number in the sample that treats hazardous waste on-site is given by




Therefore, the expected number in the sample that treats hazardous waste on-site is 0.383.
b. Find the probability that 4 of the 10 selected facilities treat hazardous waste on-site
The probability is given by
For the given case, we have
N = 209
n = 10
r = 8
x = 4




Therefore, there is a 0.000169 probability that 4 of the 10 selected facilities treat hazardous waste on-site.