Question about 95% confidence interval for population mean

[thelazyman]

Hi,

My exam is tommorow and I do not understand how to answer this question

You are given a 95% confidence interval for a population mean is (57,65)

Can you reject the null hypothesis that u= 68 at the 5% significance level? Why?

Is the margin of error 4, how do they get results for that, i just do not understand.

Please help

Thanks