Question: An article in the Journal of Composite Materials (Dec. 1989, vol. 23, p. 1200) describes the effect of delamination on the natural frequency of beams made from composite laminates. Five such delaminated beams were subjected to loads, and the resulting frequencies were as follows (in Hz):

Does this data support the claim that the mean natural frequency is 235 Hz? Assume \(\alpha \) = 0.05 and enter the critical value.