Step 1 :Given values are: confidence level \(c = 0.95\), sample variance \(s^{2} = 20.25\), and sample size \(n = 29\).
Step 2 :Calculate the value of alpha, which is \(1 - c = 0.05\).
Step 3 :Calculate the degrees of freedom, which is \(n - 1 = 28\).
Step 4 :Calculate the chi-square values \(\chi^{2}_{\alpha/2, n-1}\) and \(\chi^{2}_{1-\alpha/2, n-1}\) using the chi-square distribution. The calculated values are \(\chi^{2}_{\alpha/2, n-1} = 44.46\) and \(\chi^{2}_{1-\alpha/2, n-1} = 15.31\).
Step 5 :Substitute these values into the formulas to calculate the confidence intervals for the variance. The calculated values are \(variance_{lower} = 12.75\) and \(variance_{upper} = 37.04\).
Step 6 :Substitute these values into the formulas to calculate the confidence intervals for the standard deviation. The calculated values are \(std\_dev_{lower} = 3.57\) and \(std\_dev_{upper} = 6.09\).
Step 7 :Final Answer: The confidence interval for the population variance is \(\boxed{(12.75, 37.04)}\). The confidence interval for the population standard deviation is \(\boxed{(3.57, 6.09)}\).