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aivan3 [116]
3 years ago
10

The number of square feet per house is normally distributed with a population standard deviation of 154 square feet and an unkno

wn population mean. If a random sample of 16 houses is taken and results in a sample mean of 1550 square feet, find a 80% confidence interval for the population mean. Round your answer to TWO decimal places.
Mathematics
1 answer:
11111nata11111 [884]3 years ago
6 0

Answer: (1500.66,1599.34)

Step-by-step explanation:

Confidence interval for population mean:

\overline{x}\pm z^*\dfrac{\sigma}{\sqrt{n}}

,where \overline{x} = Sample mean , n= Sample size, z* = critical two tailed z-value , \sigma = population standard deviation.

As per given , we have

n= 16

\sigma = 154 square feet

\overline{x}= 1550 square feet

\alpha= 1-0.80 = 0.20

Critical z-value = z_{\alpha/2}=z_{0.2/2}=z_{0.1}=1.2815

Confidence interval for population mean:

1550\pm (1.2815)\dfrac{154}{\sqrt{16}}\\\\ = 1550\pm (1.2815)\dfrac{154}{4}\\\\= 1550\pm 49.33775\\\\ =(1550-49.33775,\ 1550+49.33775)\\\\\approx (1500.66,\ 1599.34)

Required confidence interval:  (1500.66,1599.34)

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Step-by-step explanation:

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