The question is as follows:
Consider an SDOF mass-spring system. The value of the mass is known and is equal to 1 kg.
The value of the spring stiffness is unknow and based on the experience and judgement the following is assumed. Value of stiffness is in the following range [0.5, 1.5] N/m.
To have a more accurate estimate of the value of the stiffness an experiment is performed where in the natural frequency of the system is observed. The following observation are made:
Observation 1 Freq = 1.021 rad/sec
Observation 2 Freq = 1.015 rad/sec
Observation 3 Freq = 0.994 rad/sec
Observation 4 Freq = 1.005 rad/sec
Observation 5 Freq = 0.989 rad/sec
- Based on the information provided write the functional form of prior PDF.
- Plot the likelihood function with different number of observations.
- Based on the information provided write the functional form of the posterior PDF.
- Plot the posterior distribution.
My work so far:
spring constant $$k = \sqrt{{w}/{m}}$$ m = 1kg, so $$w = k^{2}$$.
$$k \sim Uniform(0.5, 1.5)$$,
so pdf of w = $$ f(w) = 2w$$
where $$w\ \epsilon\ [\sqrt{0.5},\sqrt{1.5}] $$
So prior distribution is linear in the range root(0.5), root(1.5).
$$Likelihood = L = 2^{5}(1.021*1.015..*0.989) \approx 2.04772 $$
This is what I have done so far. I am new to Bayesian inference and I am not sure how to proceed after this or if what I have done so far is correct. Pleas advice on how to find the posterior function.