Mathematics: The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day. Assume that the population standard deviation is 2.2 gallons. The mean water usage per family was found to be 15.8 gallons per day for a sample of 669 families. Construct the 90% confidence interval for the mean usage of water. Round your answers to one decimal place.

The water works commission needs to know the

pineapplepizaaaaa

06.02.2022

The 90% confidence interval is $15.66< \mu < 15.94$

Step-by-step explanation:

From the question we are told that

The population standard deviation is $\sigma = 2.2$

The sample mean is $\= x = 15.8 \ gallon$

The sample size is n = 669

From the question we are told the confidence level is 95% , hence the level of significance is

$\alpha = (100 - 90 ) \%$

=> $\alpha = 0.10$

Generally from the normal distribution table the critical value of $\frac{\alpha }{2}$ is

$Z_{\frac{\alpha }{2} } = 1.645$

Generally the margin of error is mathematically represented as

$E = Z_{\frac{\alpha }{2} } * \frac{\sigma }{\sqrt{n} }$

=> $E = 1.645 * \frac{ 2.2}{\sqrt{669} }$

=> E = 0.1399

Generally 90% confidence interval is mathematically represented as

$\= x -E < \mu < \=x +E$

=> 15.8 - 0.1399

=> $15.66< \mu < 15.94$

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sukiyoshi10

01.02.2020

2 pizza for 11 people = 4 pizza for 22 people

Step-by-step explanation:

11 /2 = 5.5 pizzas per person. 22/4 = 5.5 pizzas per persontherefore 2/11 is equivalent to 4/22

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