To estimate the average salary among people in a certain district, a marketing team obtains a simple random sample of 100 people
from that district. The team sets up the following approximate 90% confidence interval, using a normal estimate, for the unknown average salary (in dollars annually) of the district: [41500,49750]
__________ Approximately 90% of the people in the district have a salary in the interval
__________ The procedure used to construct the interval works approximately 90% of the time.
_________For the normal estimate of 90% confidence to apply, the salary distribution in the population must be approximately normal.
The interpretation is that we are 90% sure that the true average salary of the district is in this interval.
Step-by-step explanation:
x% confidence interval:
A confidence interval is built from a sample, has bounds a and b, and has a confidence level of x%. It means that we are x% confident that the population mean is between a and b.
In this question:
The 90% confidence interval for the average salary of the district is [41500,49750].
This means that we are 90% sure that the true average salary of the district is in this interval.
