Question

A random sample of monarch butterflies and a random sample of swallowtail butterflies were selected, and the difference in the average flying speed for each sample was calculated. A two-sample t-test for the difference in means was conducted to investigate whether the speed at which monarchs fly, on average, is faster than the speed at which swallowtails fly. All conditions for inference were met, and the p-value was given as 0.072.

Which of the following is a correct interpretation of the p-value?
a. The probability that monarchs fly faster than swallowtails is 0.072.
b. The probability that monarchs and swallowtails fly at the same speed is 0.072.
c. Assuming that monarchs and swallowtails fly at the same speed on average, the probability of observing a difference equal to or greater than the sample difference is 0.072.
d. Assuming that monarchs fly faster than swallowtails on average, the probability of observing a difference equal to or greater than the sample difference is 0.072.
e. Assuming that monarchs fly faster than swallowtails on average, the probability of the monarchs and swallowtails flying at the same speed is 0.072.

Answer 1

Answer: c. Assuming that monarchs and swallowtails fly at the same speed on average, the probability of observing a difference equal to or greater than the sample difference is 0.072.

Explanation:

The p-value simply tells an individual how how possible it is that the data used for a particular research happened under the null hypothesis. It measures that an observed difference might have just happened due to a random chance.

The correct interpretation of the p-value of 0.072 is that assuming that monarchs and swallowtails fly at the same speed on average, the probability of observing a difference equal to or greater than the sample difference is 0.072.