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patriot [66]
3 years ago
10

35. In a simple random sample of 25 high school students, the sample mean of the SAT scores was 1450, and the sample variance wa

s 900. Assume that the data come from a normal distribution , a 95.4 % Confidence interval for the population mean is a. 1450 +/- 180 b. 1450 +/- 18 c. 1450 +/- 12 d. 1450 +/- 360
Mathematics
1 answer:
Tatiana [17]3 years ago
3 0

Answer:

1450-2.0\frac{30}{\sqrt{25}}=1450-12    

1450+2.0\frac{30}{\sqrt{25}}=1450+12    

And the best option would be:

c. 1450 +/- 12

Step-by-step explanation:

Information provided

\bar X=1450 represent the sample mean for the SAT scores

\mu population mean (variable of interest)

s^2 = 900 represent the sample variance given

n=25 represent the sample size  

Solution

The confidence interval for the true mean is given by :

\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}   (1)

The sample deviation would be s=\sqrt{900}= 30

The degrees of freedom are given by:

df=n-1=2-25=24

The Confidence is 0.954 or 95.4%, the value of \alpha=0.046 and \alpha/2 =0.023, assuming that we can use the normal distribution in order to find the quantile the critical value would be z_{\alpha/2} \approx 2.0

The confidence interval would be

1450-2.0\frac{30}{\sqrt{25}}=1450-12    

1450+2.0\frac{30}{\sqrt{25}}=1450+12    

And the best option would be:

c. 1450 +/- 12

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Answer:

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Step-by-step explanation:

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The expression for the total quantity is;

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replacing;

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The ratio of the amount of flour to the amount of buttermilk=99:1

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kiruha [24]
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Answer:

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Step-by-step explanation:

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