Question

In: Statistics and Probability

The water works commission needs to know the mean household usage of water by the residents...

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.

Solutions

Expert Solution

Solution :

Given that,

= 15.8 gallons

= 2.2 gallons

n = 669

At 90% confidence level the z is ,

  = 1 - 90% = 1 - 0.90 = 0.10

/ 2 = 0.10 / 2 = 0.05

Z/2 = Z0.05 = 1.645

Margin of error = E = Z/2* (/n)

= 1.645 * (2.2 / 669)

= 0.1

At 90% confidence interval estimate of the population mean is,

- E < < + E

15.8 - 0.1 < < 15.8 + 0.1

15.7 < < 15.9

(15.7 , 15.9)

orchestra answered 1 year ago
Next > < Previous

Related Solutions

The water works commission needs to know the mean household usage of water by the residents...
The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day. They would like the estimate to have a maximum error of 0.1 gallons. A previous study found that for an average family the variance is 6.76 gallons and the mean is 16.1 gallons per day. If they are using a 98% level of confidence, how large of a sample is required to estimate the mean usage...
The water works commission needs to know the mean household usage of water by the residents...
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 2.3 gallons. The mean water usage per family was found to be 20.5 gallons per day for a sample of 1559 families. Construct the 90% confidence interval for the mean usage of water. Round your answers to one decimal place. lower endpoint = ? upper endpoint =?
The water works commission needs to know the mean household usage of water by the residents...
The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day. They would like the estimate to have a maximum error of 0.15 0.15 gallons. A previous study found that for an average family the variance is 3.61 3.61 gallons and the mean is 17.3 17.3 gallons per day. If they are using a 90% 90% level of confidence, how large of a sample is required to...
The water works commission needs to know the mean household usage of water by the residents...
The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day. They would like the estimate to have a maximum error of 0.15 gallons. A previous study found that for an average family the standard deviation is 2.5 gallons and the mean is 15.2 gallons per day. If they are using a 80% level of confidence, how large of a sample is required to estimate the mean...
The electric cooperative needs to know the mean household usage of electricity by its non-commercial customers...
The electric cooperative needs to know the mean household usage of electricity by its non-commercial customers in kWh per day. They would like the estimate to have a maximum error of 0.14 kWh. A previous study found that for an average family the variance is 5.29 kWh and the mean is 19.9 kWh per day. If they are using a 80% level of confidence, how large of a sample is required to estimate the mean usage of electricity? Round your...
2(c) The mean monthly household expenses of all residents in a large city is RM1250 with...
2(c) The mean monthly household expenses of all residents in a large city is RM1250 with a standard deviation of RM225. However the population distribution of household expenses is skewed to the right. Calculate the mean and standard deviation of ?̅ and describe the shape of its sampling distribution when the sample size is (i) 30; [6 marks] (ii) 100; [6 marks] (iii) sketch distribution graphs for the above scenarios. [8 marks]
1. Suppose that personal daily water usage in California is normally distributed with a mean of...
1. Suppose that personal daily water usage in California is normally distributed with a mean of 17 gallons and a standard deviation of 6 gallons. (a) What proportion of California’s population uses between 10 and 20 gallons daily? (b) The governor of California wants to give a tax rebate to the 20% of the population that uses the least amount of water. What should the governor use as the maximum daily water usage for a person to qualify for the...
Why do we call water the universal solvent? All life, as we know it, needs water....
Why do we call water the universal solvent? All life, as we know it, needs water. What is the importance, relative to water being a universal solvent, to living systems?
The mean monthly water bill for 44 residents of the local apartment complex is $⁢104. What...
The mean monthly water bill for 44 residents of the local apartment complex is $⁢104. What is the best point estimate for the mean monthly water bill for all residents of the local apartment complex?
The council wants to construct the facilities that will maximize expected daily usage by the residents...
The council wants to construct the facilities that will maximize expected daily usage by the residents of the community subject to land and cost llimitations. The usage, cost, and land data for each facility are listed below. The community has $240,000 construction budget and 24 arces of land. Because the swimming pool and tennis center must be built on the same part ot the land parcel, however, only one of these two facilities can be constructed. Formulate an optimization mode...
ADVERTISEMENT
Subjects
ADVERTISEMENT
Latest Questions
ADVERTISEMENT