It is well-known that lack of sleep impairs concentration and alertness, and this might be due partly to late night food consumption. A 2015 study took 44 people aged 21 to 50 and gave them unlimited access to food and drink during the day, but allowed them only 4 hours of sleep per night for 3 consecutive nights. On the fourth night, all participants again had to stay up until 4 am, but this time participants were randomized into two groups; one group (A) was only given access to water from 10 pm until their bedtime at 4 am while the other group (B) still had unlimited access to food and drink for all hours. The group (A) performed significantly better on tests of reaction time and had fewer attention lapses than group (B).a. What are the explanatory and response variables? b. Is this nu observational study or a randomized experiment? c. Can we conclude that eating late at night worsens some of the typical effeets of alcep deprivation (reaction time and attention lapses)? d. Are there likely to be confounding variables? Why or why not?

a) The explanatory variable in this case is the food and sleep hours given to the groups and the response variable is the performance or the reaction time.

b) It is a randomized experiment as the people are given food and water and is under the influence of the study head.

c) From the detailed summary given, we can conclude that eating late worsens the effects of alcep depreviation as the group A was not given food and performed better than the group B who which had access to food and water.

d.Confounding variables are the age 21-50, the gender of people who took part in study and the type of food. Because changing these will result in different results.