Weights (in grams) of two cricket bat models were tested. Model P showed a standard deviation of 15 g, while model Q showed a standard deviation of 9 g. Which of the following inferences is valid?
a) Model P has less variability in weight than model Q.
b) The variability in weights of the two models cannot be judged without knowing their mean weights.
c) Model Q has less variability in weight than model P.
d) Both models exhibit nearly the same level of variability.