A city planner wants to estimate the average monthly residential water

xnlghtmarexgo

xnlghtmarexgo

Answered question

2021-12-04

A city planner wants to estimate the average monthly residential water usage in the city. He selected a random sample of 37 households from the city, which gave the mean water usage to be 3410.30 gallons over a one-month period. Based on earlier data, the population standard deviation of the monthly residential water usage in this city is 387.60 gallons. Make a 95 % confidence interval for the average monthly residential water usage for all households in this city.
Round your answers to two decimal places.

Answer & Explanation

Ida Perry

Ida Perry

Beginner2021-12-05Added 20 answers

Step 1
The sample mean is 3410.30 gallons.
Population standard deviation, σ is 387.60 gallons.
The sample size, n is 37.
Step 2
The z-critical value for 95% confidence interval is 1.96.
The 95% confidence interval can be calculated as follows:
CI=x±z(σn)
=3410.30±1.96(387.6037)
=3410.30±124.89
=(3285.41,3535.19)
The 95 % confidence interval for the average monthly residential water usage for all households in this city is 3285.41 and 3535.19.

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