Answer:
d. We are 95% confident that the true proportion of county residents who want the law changed is between 29% and 37%.
Step-by-step explanation:
Meaning of a confidence interval:
A x% confidence interval being between a and b means that we are x% sure that the true population proportion is between a and b.
In this question:
Sample of 600, proportion who wanted to change the law was 33% with a margin of error of +/- 4% (with 95% confidence). This implies:
From the concept of confidence interval above, the correct answer is:
d. We are 95% confident that the true proportion of county residents who want the law changed is between 29% and 37%.
Ming works as a quality assurance analyst at a bottling factory. She wants to use a one-sample z interval to estimate what proportion of 500 ml bottles are underfilled. She wants the margin of error to be no more than 4% at 90% confidence. What is the smallest sample size required to obtain the desired margin of error?
a) 271
b) 423
c) 651
d) 888
Answer:
Sample size is [tex]n=423[/tex]
Step-by-step explanation:
Given that,
Margin of error [tex]=4[/tex]%
Confidence level [tex]=90[/tex]%
Suppose, sample proportion[tex]=0.5[/tex]
i.e. [tex]\hat{P}=0.5[/tex]
We know that,
Margin of error [tex]=2^*\sqrt{\frac{\hat{p}(1-\hat{p})}{n} }[/tex]
∴ [tex]1.64\sqrt{\frac{0.5(0.5)}{n} } \leq 4\%[/tex]
[tex]\Rightarrow 1.64\sqrt{\frac{0.25}{n} } \leq 0.04[/tex]
[tex]\Rightarrow \frac{0.5}{\sqrt{n} } \leq \frac{0.04}{1.64}[/tex]
[tex]\Rightarrow \frac{0.5}{\sqrt{n} } \leq 0.0243[/tex]
[tex]\Rightarrow \sqrt{n}\geq \frac{0.5}{0.0243}[/tex]
[tex]\Rightarrow \sqrt{n}\geq 20.57[/tex]
squaring on both side,
∴ [tex]n=423.1249[/tex]
Hence, the sample size is,
[tex]n=423[/tex]
Hence, the correct option is [tex](b).[/tex]
Answer:
423
Step-by-step explanation:
Asphere has a radius of 27 inches. A horizontal plane passes through the center of the sphere.
Part 1 out od 2
Describe the cross section formed by the plane and the sphere.
9514 1404 393
Answer:
circle of radius 27 inches
Step-by-step explanation:
Anywhere a plane cuts a sphere, the cross section is a circle. When the plane includes the center of the sphere, the circle has the same radius the sphere has.
The cross section is a circle of radius 27 inches.
Luis solves the following system of equations by elimination.
5s+ 3t = 30
2s+3t=-3
What is the value of s in the solution of the system?