A study is made of the effect of curing temperature on the compressive strength of a certain type of concrete. Five concrete specimens are cured at each of four temperatures, and the compressive strength of each specimen is measured (in MPa). The results are as follows:

Temperature (C) Strengths

10 30.0 27.7 31.1 31.3

20 35.9 36.8 35.0 34.6

30 38.3 37.0 37.5 36.1

Use these data to compute an ANOVA test for equality of the 3 means with = 0.05.