02.02 LC In one study on the effect of coconut oil on hair growth, 140 subjects who acknowledged being long-time coconut oil users had their hair growth compared with those of 140 people who had never used coconut oil. In a second study, 80 subjects were randomly chosen to use coconut oil and 80 were chosen to use a placebo. Identify the types of studies performed.

Both studies were controlled experiments.

Step-by-step explanation:

Since in the question it is mentioned that there is a study on the impact of coconut oil on the hair growth.

There is 140 subjects who used the coconut oil for the long time and the other 140 people does not use the ooil

Also 80 subjects would be randomly selected for coconut oil and 80 would be selected to use for placebo

So this two studies represents the controlled experiments and the same is to be considered

The first was a observational, the second was a controlled experiment

1. 3. can also be expressed as (22/7)

2. -4.5

3. 3.6

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