Y factor for noise figure measurement

[Keefe]

Mixed signal and RF test
I need assistance in solving part b for the problem statement shown below. Part a is solved and shown below using the equations provided by the professor's notes. I am not certain how to approach part b of the problem statement. Thank you in advance.

 

[vfone]

NF = [ENR/(Y-1)] where NF, ENR and Y are linear values
NF(dB) = 10*log{[(500/290)-1]/[(1.89/1.6)-1]} = 6.01dB

Three Sigma Limits Statistical Calculation, With an Example

Three-Sigma Limits is a statistical calculation that refers to data within three standard deviations from a mean.

www.investopedia.com

 

[Keefe]

NF = [ENR/(Y-1)] where NF, ENR and Y are linear values
NF(dB) = 10*log{[(500/290)-1]/[(1.89/1.6)-1]} = 6.01dB

Three Sigma Limits Statistical Calculation, With an Example

Three-Sigma Limits is a statistical calculation that refers to data within three standard deviations from a mean.

www.investopedia.com

Thank you !