Of 1000 randomly selected cases of lung cancer 843 resulted in death within 10 years. Construct a 95\% two-sided confidence interval on the death rate from lung cancer. How large must the sample if we wish to be at least 95\% confident that the error in estimating p is less than 0.03 regardless of the value of p?

UkusakazaL

UkusakazaL

Answered question

2021-08-01

Of 1000 randomly selected cases of lung cancer 843 resulted in death within 10 years. Construct a 95% two-sided confidence interval on the death rate from lung cancer.
a) Construct a 95% two-sides confidence interval on the death rate from lung cancer. Round your answer 3 decimal places.
?p?
b) Using the point estimate of p obtained from the preliminary sample what sample size is needed to be 95% confident that the error in estimatimating the true value of p is less than 0.00?
c) How large must the sample if we wish to be at least 95% confident that the error in estimating p is less than 0.03 regardless of the value of p?

Answer & Explanation

facas9

facas9

Beginner2021-08-09Added 1 answers

a. Consider the n=1000 and x=843. The point estimate is, P^=10.843=0.157
At 95% confidence level.
α=10.95
α=0.05
α2=0.025
Zα2=Z0.025
Zα2=1.960
The margin of the error is,
E=Zα2p^(1p^)n=1.960.843(0.157)1000=0.023
So, the 95% confidence interval for the population p
0.8430.023p0.843+0.023
0.820p0.866


b. Consider the margin error,
E=0.03
n=(Zα2E)2P^(1P^)=(1.960.03)20.843×0.157=564.93=565


c.  For p less than 0.03, the sample size is obtained as,
n=(Zα2E)2P^(1P^)=(1.960.03)20.5×0.5=1067.11=1068

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