The null hypothesis is the hypothesis that is assumed to be true. It is an expression that is the opposite of what the researcher predicts.
The alternative hypothesis is what the researcher expects or predicts. It is the statement that is believed to be true if the null hypothesis is rejected.
From the given situation,
news article says that high school students are currently spending an average of 15 hours per week doing homework online. This is the null hypothesis.
H0: µ = 15 hours
You don't think this is an accurate estimate, although you're not sure whether the real value is higher or lower. This is the alternative hypothesis.
