Which inequality is true for all real numbers? check all that apply. 1.a – b < a + b 2.ac ≥ bc 3.If a ≥ b, then a + c ≥ b + c
1 answer:
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Answer:
We are confident that the true mean for the average income of all U.S. households is between (58820;71180)
Step-by-step explanation:
Information provided
represent the sample mean for the average income of all US households
population mean
s=15000 represent the sample standard deviation
n=25 represent the sample size
Confidene interval
The confidence interval for the true mean of interest is given by the following formula:
(1)
The degrees of freedom are given by:
The Confidence level is is 0.95 or 95%, then the significance is and
, the critical value for this case would be
Replacing in formula (1) we got:
We are confident that the true mean for the average income of all U.S. households is between (58820;71180)