Multiple choice but can you also explain me

1- The null hypothesis.

states that the treatment has no effect

is denoted by the symbol H1

is always stated in terms of sample statistics

All of the other choices are correct.

2- The critical region for a hypothesis test consists of.

outcomes that have a very low probability whether or not the null hypothesis is true

outcomes that have a high probability whether or not the null hypothesis is true

outcomes that have a very low probability if the null hypothesis is true

outcomes that have a high probability if the null hypothesis is true

3- A researcher wants to see if an after school program raises grades. She collects grade data on 20 children who participate in the after school program. She intends to compare this sample to the population of all students at the school. The one-tailednull hypothesis.

grades in the after school program will be no different than those in the rest of the school

grades in the after school program will be lower than those in the rest of the school

grades in the after school program will be higher than those in the rest of the school

grades in the after school program will be lower than, or equal to, than those in the rest of the school

4- In the normal distribution, what percentage of scores fall below z = -1.65? Round to a whole number.

1.65%

5%

50%

95%