Engineering Homework Help

Hi,

You will find the file Excel help you to answer this questions.

I have this assignment I need answer this questions:

Problem 1
A pressure measuring instrument has the input range of 0-200 kPa and the output range of 0-200 kPa
(sensitivity of K = 1). To characterize random uncertainty of the instrument, twelve pressure
measurements were made of a certain unknown but constant pressure source, giving the following
outputs in kPa: 125, 128, 129, 122, 126, 125, 125, 130, 126, 127, 124, and 123.

a) How would you describe the precision error (repeatability) of this instrument (at 95%
confidence)? Use % of full scale output (FSO).

b) The same instrument was used to measure an unknown pressure (not the one from the
calibration) and the reading was 110 kPa. How would you report this result and its precision
component of uncertainty at 95%? Use the result from (a).

c) The same instrument was used to measure an unknown pressure (not the one from the
calibration) four times and the average value of the readings was 110 kPa. How would you
report this result and its precision component of uncertainty at 95%? Use the result from (a).

d) What other information is needed (missing) to correctly estimate the overall measurement
uncertainties in cases (b) and (c)?

Problem 2
The attached Excel file contains the output of 10 repeats of pressure transducer calibration results
obtained in random order. The calibration input is pressure (kPa) and the instrument output is voltage
(mV). Graph and analyze the calibration data and determine:

(a) Mean value and precision error (repeatability) at each pressure setting (at 95% confidence);

(b) Linear calibration curve equation

Then find and tabulate the following instrument characteristics:

(c) Range

(d) Full-scale output

(e) Sensitivity

(f) Zero offset error (% FSO)

(g) Linearity error (% FSO)

(h) Precision error (% FSO)