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What is the length of s=8.57, n=300, confidence level=95%

Sagot :

Answer:

The length of the interval is of 1.8672.

Step-by-step explanation:

Length of a confidence interval:

Margin of error multiplied by 2.

Confidence interval:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.95}{2} = 0.025[/tex]

Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.025 = 0.975[/tex], so Z = 1.96.

Now, find the margin of error M as such

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

s=8.57, n=300

[tex]\sigma = 8.25, n = 300[/tex]

Margin of error:

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

[tex]M = 1.96\frac{8.25}{\sqrt{300}}[/tex]

[tex]M = 0.9336[/tex]

Length:

2*0.9336 = 1.8672

The length of the interval is of 1.8672.