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Reading at Bedtime It is well-documented that watching TV, working on a computer, or any other activity involving artificial light can be harmful to sleep patterns. Researchers wanted to determine if the artificial light from e-Readers also disrupted sleep. In the study, 12 young adults were given either an iPad or printed book for four hours before bedtime. Then, they switched reading devices. Whether the individual received the iPad or book first was determined randomly. Bedtime was \(10 \mathrm{P.M}\). and the time to fall asleep was measured each evening. It was found that participants took an average of 10 minutes longer to fall asleep after reading on an iPad. The \(P\) -value for the test was \(0.009 .\) (a) What is the research objective? (b) What is the response variable? It is quantitative or qualitative? (c) What is the treatment? (d) Is this a designed experiment or observational study? What type? (e) The null hypothesis for this test would be that there is no difference in time to fall asleep with an e-Reader and printed book. The alternative is that there is a difference. Interpret the \(P\) -value.

Step by step solution

01

- Determine the Research Objective

The research objective is the purpose of the study, which in this case is to determine if the artificial light from e-Readers (specifically iPads) disrupts sleep patterns.

02

- Identify the Response Variable

The response variable is the main variable of interest that is measured in the experiment. Here, it is the time taken to fall asleep. The type of the response variable is quantitative because it is a numerical measurement.

03

- Define the Treatment

The treatment in this study is the type of reading device used before bedtime. The two treatments are reading on an iPad and reading a printed book.

04

- Identify the Study Design

The study is a designed experiment because the researchers actively manipulated the treatments (type of reading device) and randomly assigned the order in which they were received. This specific design is a crossover study where each participant receives both treatments in a random order.

05

- Interpret the P-value

The null hypothesis for the test is that there is no difference in time to fall asleep between using an e-Reader and a printed book. The alternative hypothesis is that there is a difference. A p-value of 0.009 indicates strong evidence against the null hypothesis, suggesting that the type of reading device does significantly affect the time taken to fall asleep.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Research Objective

The research objective is the main purpose or goal that the study aims to achieve. In this exercise, the objective was clear: Researchers wanted to find out if artificial light from e-Readers disrupts sleep patterns. This targeted the specific question of whether using devices like iPads before bedtime affects how quickly individuals fall asleep. Understanding the research objective helps to clarify the focus and direction of the study, forming the basis for designing the experiment and analyzing the results.

Response Variable

The response variable is what researchers measure to determine the effect of the treatment or intervention. In this study, the response variable is the time it takes for participants to fall asleep after using either an iPad or a printed book. This variable is quantitative because it can be expressed in numerical terms, specifically in minutes. Quantitative response variables provide data that can be analyzed using statistical methods to draw meaningful conclusions.

Designed Experiment

A designed experiment is one where researchers actively manipulate one or more treatments to observe their effect on the response variable. In this case, the treatment is the type of reading device used before bedtime (iPad vs. printed book). The experiment is specifically designed to compare these treatments by having participants use each device in a randomized order. This approach helps to minimize biases and confounding variables, ensuring that the observed effects can be attributed to the treatment itself. This particular study used a 'crossover' design, which means each participant experienced both treatments, improving the reliability of the results.

P-Value Interpretation

The p-value in statistical tests helps determine the significance of the results. It represents the probability of observing the results, or something more extreme, if the null hypothesis is true. In this study, the null hypothesis was that there is no difference in the time to fall asleep when using an e-Reader compared to a printed book. The p-value obtained was 0.009, which is much lower than typical significance levels (like 0.05). This low p-value suggests strong evidence against the null hypothesis, indicating that the type of reading device does indeed have a significant impact on how long it takes to fall asleep.

Crossover Study

A crossover study is a type of experimental design where participants receive multiple treatments in a random order. In this study, each participant read both an iPad and a printed book before bedtime, but the order in which they received these treatments was randomized. This design is beneficial because it allows each participant to serve as their own control, reducing the variability caused by differences between individuals. By comparing the same person’s response to each treatment, researchers can draw more robust conclusions about the effects of the treatments.