Susan owns a chocolate store. She sells her chocolate by the gram and needs to compare the weights of two chocolate batches. She randomly selects 100 pieces from each batch. The distrubition of both samples are normal.

Question

Batch 1 - (Mean Weight) 56 grams
Standard Deviation - 6 grams
Batch 2 - (Mean Weight) 40 grams
Standard Deviation - 6 grams

Which statement is true?
A. Batch 1 has higher degree or variability than batch 2
B. Every chocolate in batch 1 is lighter than every chocolate in batch 2
C. The difference in mean weight show that the populations are different
D. The fact that the standard deviations are equal means these populations are about the same.

Answer 1

If you are not sure of the correct answer, try to eliminate the wrong alternatives.

A. since SDs are equal, no.

B. With SDs of 6, there seems to overlap. 56 - 2SD = 44. 40 + 2SD = 52.

D. Nope, means differ 2.67 SD.

Guess what that leaves us with?