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Chapter 4: Q. 68 (page 265)

The effects of daycare Does daycare help low-income children stay in school and hold good jobs later in life? The Carolina Abecedarian Project (the name suggests the ABCs) has followed a group of 111 children for over 40 years. Back then, these individuals were all healthy but low-income black infants in Chapel Hill, North Carolina. All the infants received nutritional supplements and help from social workers. Half were also assigned at random to an intensive preschool program. Results? Children who were assigned to the preschool program had higher IQ鈥檚, higher standardized test scores, and were less likely to repeat a grade in school.

a. Explain how this experiment used comparison.

b. Explain the purpose of randomly assigning the infants to the two treatments.

c. Name two variables that were controlled in this experiment and why it was beneficial to

control these variables.

d. Explain how this experiment used replication. What is the purpose of replication in this

context?

Short Answer

Expert verified

(a) The experiment uses comparison by comparing students' sending of pre-school program and not sending them.

(b) The purpose of randomly assigning students is to give results that are accurate.

(c) The two variables that are controlled are healthiness and low-income black infants, and these are beneficial to predict the best result.

(d) The treatment use replication because treatment is given to different students some are more healthy and some are less.

Step by step solution

01

Part (a) Step 1: Given Information

We are given the experiment where they are comparing students who have attended preschool programs, and we have to find out how the experiment uses comparison.

02

Part (a) Step 2: Explanation

According to the question, the project is comparing students who have gone to a pre-school program with those who have not attended the program, which states that we have used the principle of comparison.

Hence, in this way the researchers are using comparison operator.

03

Part (b) Step 1: Given Information

We are given the experiment where they are comparing students who have attended preschool programs, and we have to find out the purpose of randomly assigning the infants to the two treatments.

04

Part (b) Step 2: Explanation

According to the question, there are one hundred eleven students, and researchers want to observe the improvement in students by assigning them to pre-school programs and by not assigning them. For that, researchers have to choose the students randomly to send in pre-school programs.

05

Part (c) Step 1: Given Information

We are given the experiment where they are comparing students who have attended preschool programs, and we have to find out the two variables that are controlled in the experiment.

06

Part (c) Step 2: Explanation

According to the question, there are two variables: healthy and low-income black infants. As the healthiness increases, the students will be more intelligent, have more memory, and their language skills will be more accurate. Hence, the increase in healthiness will affect the results. So, it is necessary to control these two variables.

07

Part (d) Step 1: Given Information

We are given the experiment where they are comparing students who have attended preschool programs, and we have to find out the purpose of using replication in this experiment.

08

Part (d) Step 2: Explanation

According to the question, babies are researched by two things, and for one treatment, that is to send the students in a pre-school program, there will be fifty six and the remaining will not attend a pre-school program or vice-versa. Hence, this proves that an experiment uses replication because it is necessary to use to have an accurate result.

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