hypothesis testing PMCC

A geyser is a hot spring which erupts from time to time. For two geysers, the duration of each
eruption, x minutes, and the waiting time until the next eruption, y minutes, are recorded.
(a) For a random sample of 50 eruptions of the first geyser, the correlation coefficient between x
and y is 0.758.
The critical value for a 2-tailed hypothesis test for correlation at the 5% level is 0.279.
Explain whether or not there is evidence of correlation in the population of eruptions.


[3] So there is sufficient evidence of correlation
0.758 > 0.279

why is the crit value not halved?