50 people are randomly selected and the accuracy of their wristwatches is checked, with positive errors representing watches that are ahead of the correct time and negative errors representing watches...

50 people are randomly selected and the accuracy of their wristwatches is checked, with positive errors representing watches that are ahead of the correct time and negative errors representing watches that are behind the correct time. The 50 values have a mean of 93sec and a population standard deviation of 223sec. Use a 0.02 significance level to test the claim that the population of all watches has a mean of 0sec (use a two-sided alternative).

The test statistic is

The P-Value is