A school authority claims that the average percentage marks of students is 68. A researcher has taken a well-designed survey and his sample mean is 64.5 and sample standard deviationis 2. The sample size is 300. Which statement is correct?

1. The sample size should be much more.

2. The result of the survey is not statistically significant.

3. The difference existsdue to chancesince the test statistic issmall.

4. The result of the survey is statistically significant.