The statements about the study are:
Let's analyze each statement:
1) This study uses random sampling.
This is true, as the children are randomly selected, so there is no bias.
2) This study uses a repeated measures design.
Is really important to repeat any given study, and this one does it, so this option is correct. This study was repeated 4 times, so this is true.
3) This study uses blinding.
Blinding is when the participants of the study don't know all the important information for the study. Here there is no clarification of blinding being used, so we assume this is false.
4) This study uses blocking.
Blocking is when the sample is divided in "blocks" that are similar between them, as you can see, in this study the children are divided in blocks, so this is true.
5) This study uses a control group.
The control group would be a group that is left alone and "don't participate" in the experiment, so then the results can be compared after. In this experiment, the control group is the one that has no screen time, so this statement is correct.
If you want to learn more about studies, you can read:
https://brainly.com/question/14470673