Answer:
-4.42
Step-by-step explanation:
Given the following :
Population mean (pm) = 8 hours
Sample mean (sm) = 6.9 hours
Number of observations (n) = 101 students
Sample standard deviation (sd) = 2.5
Using the t-statistic formula :
[(sm - pm) / (sd/√n)]
Hence,
[(6.9 - 8) / (2.5/√101)]
[(-1.1) / (2.5/10.05)]
-1.1 / 0.2487562
= −4.422
The test statistic = - 4.42 to the nearest hundredth.
P(2 or H) = P(2) + P(H) - P(2 and H)
What is the probability of getting a 2 P(2)? = 1/6
What is the probability of getting heads P(H)? = 1/2
P(2 and H) is the product of those two events since the events are independent. = 1/6 * 1/2 = 1/12
P(2 or H) = P(2) + P(H) - P(2 and H)
P(2 or H) = 1/6 + 1/2 - 1/12 = 7/12
Just substitute - 2 into x and solve.
Answer:
pift^2(or your third option) is the area of a circle with a radius of 1.
Answer:
a) A sample size of 5615 is needed.
b) 0.012
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 is:
99.5% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
(a) Past studies suggest that this proportion will be about 0.2. Find the sample size needed if the margin of the error of the confidence interval is to be about 0.015.
This is n for which M = 0.015.
We have that 
A sample size of 5615 is needed.
(b) Using the sample size above, when the sample is actually contacted, 12% of the sample say they are not satisfied. What is the margin of the error of the confidence interval?
Now 
.
We have to find M.
