A random sample of the records of single births was selected from each of four populations. The weights (grams) of the babies at birth were as follows:

Sample A BCD 2946 3186 2300 2286 2913 2857 2903 2938 2280 3099 2572 2952 3685 2761 2584 2348 2310 3290 2675 2691 2582 2937 2571 2858 3002 3347 2414 2408 2008 2850 2762 Do these data provide sufficient evidence to indicate, at the .05 level of significance, that the four populations differ with respect to mean birth weight? Test for a significant difference between all possible pairs of means.