4. Correct. The answer is false
A type I error is made by rejecting a null hypothesis when is true.
We know that 't' calculated is:
(34.8 - 30)/16.7332 = 0.286855
And 't' from table for 60 degree of freedom is 1.671 (This value is for one tail because the alternative hypothesis is 'greater than').
Since 't' calculated (tc) is less than t from the table (tt) this value (tc) lies in the region f acceptance the null hypothesis. Then we accept the null hypothesis which states: b = 30 and we reject the null hypothesis we are committing an error type I.
Therefore the probability of making type error I is a = 0.05 or 5%.