Statistics using R

Download this file and type or paste your responses after the questions.

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A college professor wants to determine the best way to present an important topic to his class. He has the following three choices: (1) he can lecture, (2) he can lecture and assign supplementary reading, or (3) he can show a film and assign supplementary reading. He decides to do an experiment to evaluate the three options. He solicits 27 volunteers and randomly assigns 9 to each of three conditions. In condition 1, he lectures to the students. In condition 2, he lecture and assigns supplementary reading. In condition 3 the students see a film on the topic plus receive the same supplementary reading as the students in condition 2. The students are subsequently tested on the material. The following scores (percentage correct) were obtained.

Condition 1: 92, 86, 87, 76, 79, 86, 91, 81, 83

Condition 2: 86, 93, 97, 81, 94, 89, 98, 90, 91

Condition 3: 81, 80, 72, 82, 83, 89, 76, 88, 83

These data are available in the Week 14 module of D2L in the csv file called “Important”

Identify the appropriate statistical test of this study (2 points)

Identify the research question under consideration in this study (2 points)

Identify an appropriate Null Hypothesis for the study (2 points)

Identify an appropriate Alternative Hypothesis for the study (2 points)

Using R, perform the statistical test you identified in the first question (6 points)

Perform all possible 2 group comparisons for the results of the experiment (4 point)

Using the results of your comparisons, identify the method that works best (if any) and explain why you made this choice (4 points)

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A cognitive psychologist believes that a particular drug improves short-term memory. The drug is safe, with no side effects. An experiment is conducted in which 8 randomly selected subjects are given the drug and then given a short time to memorize a list of 10 words. The subjects are then tested for retention 15 minutes after the memorization period. The number of words correctly recalled by each subject is as follows: 8, 9, 10, 6, 8, 7, 9, 7. Over the past few years the psychologist has collected a lot of data using this task with similar subjects but without the drug. Although he has lost the original data, he remembers that the mean was 6 words correctly recalled and that the data were normally distributed.

You may do this problem by hand or using R (or a combination of R with hand calculations). If you do the calculations by hand, put a scan or photo in the dropbox showing the calculations. If you use R, simply cut and paste your results into this file. If you use R you will need to create a data file with the results pf the experiment. You may do this in Excel, in a text editor, or by creating a data vector in R as we did early in the semester.

Identify the appropriate statistical test of this study (2 points)

Identify the research question under consideration in this study (2 points)

Identify an appropriate non-directional Null Hypothesis for the study (2 points)

Identify an appropriate Alternative hypothesis for the study (2 points)

Perform the statistical test you identified in the first question (6 points)

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On the basis of her experience with clients, a clinical psychologist thinks that depression may affect sleep. She decides to test this idea. The sleep of 9 depressed patients and 8 normal controls is monitored for 3 successive nights.The average number of hours slept by each subject during the last two nights is shown in the following table.

Depressed: 7.1, 6.8, 6.7, 7.3, 7.5, 6.2, 6.9, 6.5, 7.2

Normal: 8.2, 7.5, 7.7, 7.8, 8.0, 7.4, 7.3, 6.5

These data are available in the Week 14 module of D2L in the csv file called “Sleep”

Identify the appropriate statistical test of this study (2 points)

Identify the research question under consideration in this study (2 points)

Identify an appropriate non-directional Null Hypothesis for the study (2 points)

Identify an appropriate Alternative hypothesis for the study (2 points)

Using R perform the statistical test you identified in the first question (6 points)

Statistics using R

Download this file and type or paste your responses after the questions.

*******************************************************************************************************************

A college professor wants to determine the best way to present an important topic to his class. He has the following three choices: (1) he can lecture, (2) he can lecture and assign supplementary reading, or (3) he can show a film and assign supplementary reading. He decides to do an experiment to evaluate the three options. He solicits 27 volunteers and randomly assigns 9 to each of three conditions. In condition 1, he lectures to the students. In condition 2, he lecture and assigns supplementary reading. In condition 3 the students see a film on the topic plus receive the same supplementary reading as the students in condition 2. The students are subsequently tested on the material. The following scores (percentage correct) were obtained.

Condition 1: 92, 86, 87, 76, 79, 86, 91, 81, 83

Condition 2: 86, 93, 97, 81, 94, 89, 98, 90, 91

Condition 3: 81, 80, 72, 82, 83, 89, 76, 88, 83

These data are available in the Week 14 module of D2L in the csv file called “Important”

Identify the appropriate statistical test of this study (2 points)

Identify the research question under consideration in this study (2 points)

Identify an appropriate Null Hypothesis for the study (2 points)

Identify an appropriate Alternative Hypothesis for the study (2 points)

Using R, perform the statistical test you identified in the first question (6 points)

Perform all possible 2 group comparisons for the results of the experiment (4 point)

Using the results of your comparisons, identify the method that works best (if any) and explain why you made this choice (4 points)

*******************************************************************************************************************

A cognitive psychologist believes that a particular drug improves short-term memory. The drug is safe, with no side effects. An experiment is conducted in which 8 randomly selected subjects are given the drug and then given a short time to memorize a list of 10 words. The subjects are then tested for retention 15 minutes after the memorization period. The number of words correctly recalled by each subject is as follows: 8, 9, 10, 6, 8, 7, 9, 7. Over the past few years the psychologist has collected a lot of data using this task with similar subjects but without the drug. Although he has lost the original data, he remembers that the mean was 6 words correctly recalled and that the data were normally distributed.

You may do this problem by hand or using R (or a combination of R with hand calculations). If you do the calculations by hand, put a scan or photo in the dropbox showing the calculations. If you use R, simply cut and paste your results into this file. If you use R you will need to create a data file with the results pf the experiment. You may do this in Excel, in a text editor, or by creating a data vector in R as we did early in the semester.

Identify the appropriate statistical test of this study (2 points)

Identify the research question under consideration in this study (2 points)

Identify an appropriate non-directional Null Hypothesis for the study (2 points)

Identify an appropriate Alternative hypothesis for the study (2 points)

Perform the statistical test you identified in the first question (6 points)

*******************************************************************************************************************

On the basis of her experience with clients, a clinical psychologist thinks that depression may affect sleep. She decides to test this idea. The sleep of 9 depressed patients and 8 normal controls is monitored for 3 successive nights.The average number of hours slept by each subject during the last two nights is shown in the following table.

Depressed: 7.1, 6.8, 6.7, 7.3, 7.5, 6.2, 6.9, 6.5, 7.2

Normal: 8.2, 7.5, 7.7, 7.8, 8.0, 7.4, 7.3, 6.5

These data are available in the Week 14 module of D2L in the csv file called “Sleep”

Identify the appropriate statistical test of this study (2 points)

Identify the research question under consideration in this study (2 points)

Identify an appropriate non-directional Null Hypothesis for the study (2 points)

Identify an appropriate Alternative hypothesis for the study (2 points)

Using R perform the statistical test you identified in the first question (6 points)