A technology company is interested in studying consumer cell phone usage efficiency, particularly when it comes to completing various tasks on different screen sizes. They ask 30 subjects to complete three separate tasks (easy, normal, difficult) on two different screen sizes (5 inch, 7 inch) and record the time it takes to complete each task (in seconds). They were particularly interested in whether the time it takes to complete each type of task differed between screen sizes. Data was collected and stored in the 'Phone' data. The variables measured were:

Subject: Person identifier

Time: Time it takes to complete the task (in seconds)

Size: Screen size (5 inch, 7 inch)

Task: (Easy, Normal, Difficult)

a. Do you think the screen size or task type has an effect on the time it takes to complete task? Do you think there is an interaction between screen size and task type in their potential effect on time? To answer these questions, perform some exploratory descriptive analysis on the data. This should include both numeric summaries and appropriate graphics that aid in answering these questions.

Note: This part is purely descriptive. You are not running any formal tests here.

b. We are now interested in formally testing whether the mean time differs significantly between screen sizes and task types, specifically whether the task type's effect on time differs depending on the screen size. Run the appropriate analysis and copy and paste the output below.

c. Provide detailed summary discussing the results from this analysis. Be sure to interpret each type of effect analyzed.

d. Can you offer any advice to the technology company, assuming their goal is to increase usage efficiency?