Mechanical engineer Behnam Amin has developed an "intelligent" liquid flow valve using a miniature embedded microprocessor that harnesses the power of advanced modular electronics to control the flow. The response time of the control valve had a mean of 2.17 seconds with a standard deviation of 0.472 after performing 25 tests on the control valve. These valves are used in applications such as aircraft fuel-tank level control systems.
Construct a 99% confidence interval for the population mean response time.
Confidence interval statistics | |||
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Find a z_{c} value from a confidence level c | z_{c} | =ABS(NORMSINV((1-c)/2)) | |
Find a t_{c} value from a confidence level c and sample size n | t_{c} | =TINV(1-c,n-1) | |
Calculate an error tolerance E of a mean for n >= 30 using sx | E | =z_{c}*sx/SQRT(n) | |
Calculate an error tolerance E of a mean for n < 30 using sx. Can also be used for n >= 30. | E | =t_{c}*sx/SQRT(n) | |
Calculate a confidence interval for a population mean µ from a sample mean x and an error tolerance E | x-E<= µ <=x+E |