4. Baby walkers are seats hanging from frames that allow babies to sit upright with their legs dangling and feet touching the floor. Walkers have wheels on their legs that allow the infant to propel the walker around the house long before he or she can walk or even crawl. Typically, babies use walkers between the ages of 4 months and 11 months. Because most walkers have tray tables in front that block babies' views of their feet, child psychologists have begun to question whether walkers affect infants' cognitive development. One study compared mental skills of a random sample of those who used walkers with a random sample of those who never used walkers. Mental skill scores averaged 113 for 54 babies who used walkers (standard deviation of 12) and 123 for 55 babies who did not use walkers (standard deviation of 15). (a) Is there evidence that the mean mental skill score of babies who use walkers is different from the mean mental skill score of babies who do not use walkers? Explain your answer. (b) Suppose that a study using this design found a statistically significant result. Would it be reasonable to conclude that using a walker causes a change in mean mental skill score? Explain your answer.
4. Baby walkers are seats hanging from frames that allow babies to sit upright with their legs dangling and feet touching the floor. Walkers have wheels on their legs that allow the infant to propel the walker around the house long before he or she can walk or even crawl. Typically, babies use walkers between the ages of 4 months and 11 months. Because most walkers have tray tables in front that block babies' views of their feet, child psychologists have begun to question whether walkers affect infants' cognitive development. One study compared mental skills of a random sample of those who used walkers with a random sample of those who never used walkers. Mental skill scores averaged 113 for 54 babies who used walkers (standard deviation of 12) and 123 for 55 babies who did not use walkers (standard deviation of 15). (a) Is there evidence that the mean mental skill score of babies who use walkers is different from the mean mental skill score of babies who do not use walkers? Explain your answer. (b) Suppose that a study using this design found a statistically significant result. Would it be reasonable to conclude that using a walker causes a change in mean mental skill score? Explain your answer.
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
Use z test for difference of means. Show work please
![4. Baby walkers are seats hanging from frames that allow babies to sit upright with their legs dangling and feet
touching the floor. Walkers have wheels on their legs that allow the infant to propel the walker around the house
long before he or she can walk or even crawl. Typically, babies use walkers between the ages of 4 months and
11 months.
Because most walkers have tray tables in front that block babies' views of their feet, child psychologists have
begun to question whether walkers affect infants' cognitive development. One study compared mental skills of
a random sample of those who used walkers with a random sample of those who never used walkers. Mental
skill scores averaged 113 for 54 babies who used walkers (standard deviation of 12) and 123 for 55 babies who
did not use walkers (standard deviation of 15).
(a) Is there evidence that the mean mental skill score of babies who use walkers is different from the mean
mental skill score of babies who do not use walkers? Explain your answer.
(b) Suppose that a study using this design found a statistically significant result. Would it be reasonable to
conclude that using a walker causes a change in mean mental skill score? Explain your answer.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fbca49413-148b-49bc-9aca-0999bd714989%2F2e7d3063-b428-4510-bfc5-ca1009bcd40d%2F4x7j9ba_processed.jpeg&w=3840&q=75)
Transcribed Image Text:4. Baby walkers are seats hanging from frames that allow babies to sit upright with their legs dangling and feet
touching the floor. Walkers have wheels on their legs that allow the infant to propel the walker around the house
long before he or she can walk or even crawl. Typically, babies use walkers between the ages of 4 months and
11 months.
Because most walkers have tray tables in front that block babies' views of their feet, child psychologists have
begun to question whether walkers affect infants' cognitive development. One study compared mental skills of
a random sample of those who used walkers with a random sample of those who never used walkers. Mental
skill scores averaged 113 for 54 babies who used walkers (standard deviation of 12) and 123 for 55 babies who
did not use walkers (standard deviation of 15).
(a) Is there evidence that the mean mental skill score of babies who use walkers is different from the mean
mental skill score of babies who do not use walkers? Explain your answer.
(b) Suppose that a study using this design found a statistically significant result. Would it be reasonable to
conclude that using a walker causes a change in mean mental skill score? Explain your answer.
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