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steposvetlana [31]
3 years ago
9

A student measured the lead content of a paint sample 4 times. The standard deviation of the measurements was found to be 0.76%

of the average. Calculate the confidence interval at the 90% confidence level.
Mathematics
1 answer:
Lady_Fox [76]3 years ago
6 0

Answer:

CI =0.894%

Step-by-step explanation:

From the question we are told that:

Sample size n=4

Standard deviation \sigma=0.76\% of \=x

Confidence level \mu =90\%=0.90

Degree of Freedom Df=n-1=3

Therefore

Test T from table is given

 t=2.353

Generally the equation for Confidence interval CI is mathematically given by

 CI =t*\frac{\sigma}{\sqrt{n}}

 CI =2.353*\frac{0.76}{\sqrt{4}}

 CI =0.894%

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Answer:

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Step-by-step explanation:

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7 0
3 years ago
A researcher has collected the following sample data. The mean of the sample below is 5.
abruzzese [7]

Answer:

The coefficient of variation is 72.66%

Step-by-step explanation:

Data : 3 , 5 , 12 , 3 , 2

We are given that The mean of the sample is 5.

Formula of standard deviation =\sigma = \sqrt{\frac{\sum(x-\bar{x})^2}{n}

Substitute the values :

\sigma = \sqrt{\frac{(3-5)^2+(5-5)^2+(12-5)^2+(3-5)^2+(2-5)^2}{5}}=3.633

Coefficient of variation=\frac{\sigma}{\mu} \times 100=\frac{3.633}{5} \times 100 =72.66\%

Hence The coefficient of variation is 72.66%

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3 years ago
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Answer:

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2 years ago
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Answer:

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Step-by-step explanation:

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Step-by-step explanation:

20%

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