Posted by John on .
A group of 9 trout (considered the population) were isolated in a pond and fed a special food mixture called Grow Em Fast. At the end of the experimental period, the weights of the trout were (in grams): 124, 125, 123, 120, 124, 127, 125, 126 and 121. Another special mixture, Fatso 1B, was used in another pond. The mean of the population was computed to be 126.9 grams and the standard deviation was 1.20 grams. Which food results in a more uniform weight?
A) Grow Em Fast
B) Fatso 1B
C) No difference in uniformity of performance.
D) Insufficient information.

Math 
PsyDAG,
Calculate the standard deviation for Grow Em Fast and compare to 1.2 for Fatso 1B.
To get standard deviation, first find mean. Get difference of each score from mean, square those differences and find their sum. Divide by n (9), and the square root of that quotient will be the standard deviation. 
Math 
sam,
fatso 1b