In: Math
For this problem, carry at least four digits after the decimal
in your calculations. Answers may vary slightly due to
rounding.
The National Council of Small Businesses is interested in the
proportion of small businesses that declared Chapter 11 bankruptcy
last year. Since there are so many small businesses, the National
Council intends to estimate the proportion from a random sample.
Let p be the proportion of small businesses that declared
Chapter 11 bankruptcy last year.
(a) If no preliminary sample is taken to estimate p,
how large a sample is necessary to be 99% sure that a point
estimate p̂ will be within a distance of 0.09from
p? (Round your answer up to the nearest whole
number.)
small businesses
(b) In a preliminary random sample of 30 small businesses, it was
found that ten had declared Chapter 11 bankruptcy. How many
more small businesses should be included in the sample to
be 99% sure that a point estimate p̂ will be within a
distance of 0.090 from p? (Round your answer up to the
nearest whole number.)
more small businesses
a)
The following information is provided,
Significance Level, α = 0.01, Margin of Error, E = 0.09
The provided estimate of proportion p is, p = 0.5
The critical value for significance level, α = 0.01 is 2.576.
The following formula is used to compute the minimum sample size
required to estimate the population proportion p within the
required margin of error:
n >= p*(1-p)*(zc/E)^2
n = 0.5*(1 - 0.5)*(2.576/0.09)^2
n = 204.8079
Therefore, the sample size needed to satisfy the condition n
>= 204.8079 and it must be an integer number, we conclude that
the minimum required sample size is n = 205
Ans : Sample size, n = 205
b)
The following information is provided,
Significance Level, α = 0.01, Margin of Error, E = 0.09
The provided estimate of proportion p is, p = 0.3333
The critical value for significance level, α = 0.01 is 2.576.
The following formula is used to compute the minimum sample size
required to estimate the population proportion p within the
required margin of error:
n >= p*(1-p)*(zc/E)^2
n = 0.3333*(1 - 0.3333)*(2.576/0.09)^2
n = 182.0424
Therefore, the sample size needed to satisfy the condition n
>= 182.0424 and it must be an integer number, we conclude that
the minimum required sample size is n = 183
Ans : Sample size, n = 183