Answer
There is no difference.
Work Step by Step
The sample size is more than 25, hence the value of the test statistic: $z=\frac{(x+0.5)-n/2}{\sqrt n/2}=\frac{(123+0.5)-280/2}{\sqrt{280}/2}=-1.97.$ By using the table, the corresponding critical value: $z=\pm 2.575.$ If the value of the test statistic is in the rejection region, we reject the null hypothesis. -1.97 is between -2.575 and 2.575 hence we fail to reject the null hypothesis, hence there is no difference.
