Researchers study how the global warming affects the sea level. They wonder whether the mean of yearly differences of the sea level has increased from 4.4 mm using the level of significance α = 0.05. What does the level of significance mean in the context of the study?
A) The probability of a decision that the mean of differences would be less than 4.4 mm, when in fact the mean is still 4.4 mm.
B) The probability of a decision that the mean of differences would stay the same, when in fact it would increase.
C) The probability of a decision that the mean of differences would be greater than 4.4 mm, no matter whether it would increase in fact or not.
D) The probability of a decision that the mean of differences would stay the same, no matter whether it would increase in fact or not.
E) The probability of a decision that the mean of differences would be greater than 4.4 mm, when in fact it is still the same.

Question

Quizplus · Accepted Answer

The level of significance, α = 0.05, represents the probability of rejecting the null hypothesis when it is actually true. In this context, it means there's a 5% chance of concluding that the mean yearly difference in sea level has increased from 4.4 mm when it has not changed.

Researchers Study How the Global Warming Affects the Sea Level