12. Correct. The answer is true


Observed frequencies of tails are x1=116 and x2=84.

Expected frequencies if the coin is fair are np1=100 and np2=100. Then


χ2=(x1-np1)2/np1 + (x2-np2)2/np=(116-100)2/100 + (84-100)2/100 = 2.56+2.56=5.12.


The critical value χ20.95 for 1 degrees of freedom (n=k-1=2-1) is 3.84, we fail to reject the hypothesis that the coin is fair at 5% significance level.