In laparoscopic surgery, a video camera and several thin instruments are inserted into the patient's abdominal cavity. The surgeon uses the image from the video camera positioned inside the patient's body to perform the procedure by manipulating the instruments that have been inserted. It has been found that the Nintendo Wii™ reproduces the movements required in laparoscopic surgery more closely than other video games with its motion‑sensing interface. If training with a Nintendo Wii™ can improve laparoscopic skills, it can complement the more expensive training on a laparoscopic simulator. Forty‑two medical residents were chosen, and all were tested on a set of basic laparoscopic skills. Twenty‑one were selected at random to undergo systematic Nintendo Wii™ training for one hour a day, five days a week, for four weeks. The remaining 21 residents were given no Nintendo Wii™ training and asked to refrain from video games during this period. At the end of four weeks, all 42 residents were tested again on the same set of laparoscopic skills. One of the skills involved a virtual gall bladder removal, with several performance measures including time to complete the task recorded. The improvement (before–after) times in seconds after four weeks for the two groups are given in the tables. NOTE: The numerical values in this problem have been modified for testing purposes. Treatment 281 134 186 128 84 243 212 121 134 221 59 244 79 333 −13 −16 71 −16 71 7 144 Control 21 66 54 84 228 92 43 27 77 −29 −14 88 142 107 32 90 46 −81 68 61 44 The most common methods for formal comparison of two groups use ?¯ and ? to summarize the data. (a) What kinds of distributions are best summarized by ?¯ and ? ? Select the correct response. Skewed distributions are best summarized using ?¯ and ? . All distributions are best summarized using ?¯ and ? . Symmetric distributions are best summarized using ?¯ and ? . Bimodal distributions are best summarized using ?¯ and ? . (b) In the control group, one subject improved their time by 228 seconds. Compute ?¯ and ? for the control group, both with and without the high outlier. (Enter your answers rounded to two decimal places.) ?¯ with outlier= ? with outlier= ?¯ without outlier= ? without outlier= (c) Compute the median for the control group with and without the high outlier. (Enter your answers rounded to two decimal places.) Median with outlier= Median without outlier= What does this show about the resistance of the median and ?¯ ? Neither the mean and median are affected by the outlier. The median is less impacted by the outlier than the mean. The mean and median are affected the same by the outlier. The mean is less impacted by the outlier than the median.

In laparoscopic surgery, a video camera and several thin instruments are inserted into the patient's abdominal cavity. The surgeon uses the image from the video camera positioned inside the patient's body to perform the procedure by manipulating the instruments that have been inserted. It has been found that the Nintendo Wii™ reproduces the movements required in laparoscopic surgery more closely than other video games with its motion‑sensing interface. If training with a Nintendo Wii™ can improve laparoscopic skills, it can complement the more expensive training on a laparoscopic simulator. Forty‑two medical residents were chosen, and all were tested on a set of basic laparoscopic skills. Twenty‑one were selected at random to undergo systematic Nintendo Wii™ training for one hour a day, five days a week, for four weeks. The remaining 21 residents were given no Nintendo Wii™ training and asked to refrain from video games during this period. At the end of four weeks, all 42 residents were tested again on the same set of laparoscopic skills. One of the skills involved a virtual gall bladder removal, with several performance measures including time to complete the task recorded. The improvement (before–after) times in seconds after four weeks for the two groups are given in the tables. NOTE: The numerical values in this problem have been modified for testing purposes. Treatment 281 134 186 128 84 243 212 121 134 221 59 244 79 333 −13 −16 71 −16 71 7 144 Control 21 66 54 84 228 92 43 27 77 −29 −14 88 142 107 32 90 46 −81 68 61 44 The most common methods for formal comparison of two groups use ?¯ and ? to summarize the data. (a) What kinds of distributions are best summarized by ?¯ and ? ? Select the correct response. Skewed distributions are best summarized using ?¯ and ? . All distributions are best summarized using ?¯ and ? . Symmetric distributions are best summarized using ?¯ and ? . Bimodal distributions are best summarized using ?¯ and ? . (b) In the control group, one subject improved their time by 228 seconds. Compute ?¯ and ? for the control group, both with and without the high outlier. (Enter your answers rounded to two decimal places.) ?¯ with outlier= ? with outlier= ?¯ without outlier= ? without outlier= (c) Compute the median for the control group with and without the high outlier. (Enter your answers rounded to two decimal places.) Median with outlier= Median without outlier= What does this show about the resistance of the median and ?¯ ? Neither the mean and median are affected by the outlier. The median is less impacted by the outlier than the mean. The mean and median are affected the same by the outlier. The mean is less impacted by the outlier than the median.

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Question

Forty‑two medical residents were chosen, and all were tested on a set of basic laparoscopic skills. Twenty‑one were selected at random to undergo systematic Nintendo Wii™ training for one hour a day, five days a week, for four weeks. The remaining 21 residents were given no Nintendo Wii™ training and asked to refrain from video games during this period. At the end of four weeks, all 42 residents were tested again on the same set of laparoscopic skills. One of the skills involved a virtual gall bladder removal, with several performance measures including time to complete the task recorded. The improvement (before–after) times in seconds after four weeks for the two groups are given in the tables.

NOTE: The numerical values in this problem have been modified for testing purposes.

Treatment

281	134	186	128	84	243	212
121	134	221	59	244	79	333
−13	−16	71	−16	71	7	144

Control

21	66	54	84	228	92	43
27	77	−29	−14	88	142	107
32	90	46	−81	68	61	44

The most common methods for formal comparison of two groups use ?¯ and ? to summarize the data.

(a) What kinds of distributions are best summarized by ?¯ and ? ? Select the correct response.

Skewed distributions are best summarized using ?¯ and ? .

All distributions are best summarized using ?¯ and ? .

Symmetric distributions are best summarized using ?¯ and ? .

Bimodal distributions are best summarized using ?¯ and ? .

(b) In the control group, one subject improved their time by 228 seconds. Compute ?¯ and ? for the control group, both with and without the high outlier. (Enter your answers rounded to two decimal places.)

?¯ with outlier=

? with outlier=

?¯ without outlier=

? without outlier=

(c) Compute the median for the control group with and without the high outlier. (Enter your answers rounded to two decimal places.)

Median with outlier=

Median without outlier=

What does this show about the resistance of the median and ?¯ ?

Neither the mean and median are affected by the outlier.

The median is less impacted by the outlier than the mean.

The mean and median are affected the same by the outlier.

The mean is less impacted by the outlier than the median.

Definition Definition Middle value of a data set. The median divides a data set into two halves, and it also called the 50th percentile. The median is much less affected by outliers and skewed data than the mean. If the number of elements in a dataset is odd, then the middlemost element of the data arranged in ascending or descending order is the median. If the number of elements in the dataset is even, the average of the two central elements of the arranged data is the median of the set. For example, if a dataset has five items—12, 13, 21, 27, 31—the median is the third item in ascending order, or 21. If a dataset has six items—12, 13, 21, 27, 31, 33—the median is the average of the third (21) and fourth (27) items. It is calculated as follows: (21 + 27) / 2 = 24.

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