Industrial workers are sometimes hurt in accidents. Industrial psychologists bel
ID: 3177853 • Letter: I
Question
Industrial workers are sometimes hurt in accidents. Industrial psychologists believe that the time it takes a worker to heal depends on the worker's outlook on life. They randomly select 36 industrial workers who suffer the same kind of broken wrist: 12 that are optimistic about life, 12 that are neutral in their outlook, and 12 that are pessimistic. They measure the time (in days) that it takes each worker to heal, and use an ANOVA test to compare the mean healing times for the three groups. Their null hypothesis is
H0:optimistic=neutral=pessimistic
Please use this information to answer the next two questions.
Which of the following is the most appropriate alternative hypothesis for the psychologists' test?
The means of the differences are not 0.
All three of the population means are different from each other.
At least one of the population means is different from at least one other.
Ha:optimisticneutralpessimistic
Which of the following are requirements that the psychologists would have to satisfy, to justify completing their ANOVA test? Mark all that apply.
The largest standard deviation for the three samples has to be less than four times the smallest.
The largest variance for the three samples has to be less than four times the smallest.
The samples need to carefully matched to each other, as in a paired-data test.
The three populations (healing times for each of the three groups) need to be normal.
There must be at least 30 people in the study, all together.
There must be at least 30 people in each sample.
A study examined possible reasons for students going on academic probation. Students who spent more than 20 hours a week playing video games were classified as "heavy gamers." Of the 342 students on academic probation in the study, 127 were found to be heavy gamers.
Please use this information to answer the next three questions.
Calculate the point estimate p of the proportion of students on academic probation that are heavy gamers.
Referring to the previous question, consider the distribution of all sample proportions p^ when the sample size is 342. Calculate the mean and standard deviation of this distribution, assuming that p=0.4
Input your answers in the next two questions.
The mean is
Your Answer:
The standard deviation is
Your Answer:
The means of the differences are not 0.
All three of the population means are different from each other.
At least one of the population means is different from at least one other.
Ha:optimisticneutralpessimistic
Which of the following are requirements that the psychologists would have to satisfy, to justify completing their ANOVA test? Mark all that apply.
The largest standard deviation for the three samples has to be less than four times the smallest.
The largest variance for the three samples has to be less than four times the smallest.
The samples need to carefully matched to each other, as in a paired-data test.
The three populations (healing times for each of the three groups) need to be normal.
There must be at least 30 people in the study, all together.
There must be at least 30 people in each sample.
A study examined possible reasons for students going on academic probation. Students who spent more than 20 hours a week playing video games were classified as "heavy gamers." Of the 342 students on academic probation in the study, 127 were found to be heavy gamers.
Please use this information to answer the next three questions.
Calculate the point estimate p of the proportion of students on academic probation that are heavy gamers.
Referring to the previous question, consider the distribution of all sample proportions p^ when the sample size is 342. Calculate the mean and standard deviation of this distribution, assuming that p=0.4
Input your answers in the next two questions.
The mean is
Your Answer:
The standard deviation is
Your Answer:
Explanation / Answer
Result:
Industrial workers are sometimes hurt in accidents. Industrial psychologists believe that the time it takes a worker to heal depends on the worker's outlook on life. They randomly select 36 industrial workers who suffer the same kind of broken wrist: 12 that are optimistic about life, 12 that are neutral in their outlook, and 12 that are pessimistic. They measure the time (in days) that it takes each worker to heal, and use an ANOVA test to compare the mean healing times for the three groups. Their null hypothesis is
H0:optimistic=neutral=pessimistic
Please use this information to answer the next two questions.
Which of the following is the most appropriate alternative hypothesis for the psychologists' test?
The means of the differences are not 0.
All three of the population means are different from each other.
Answer: At least one of the population means is different from at least one other.
Ha:optimisticneutralpessimistic
Which of the following are requirements that the psychologists would have to satisfy, to justify completing their ANOVA test? Mark all that apply.
The largest standard deviation for the three samples has to be less than four times the smallest.
The largest variance for the three samples has to be less than four times the smallest.
The samples need to carefully matched to each other, as in a paired-data test.
The three populations (healing times for each of the three groups) need to be normal.
There must be at least 30 people in the study, all together.
There must be at least 30 people in each sample.
A study examined possible reasons for students going on academic probation. Students who spent more than 20 hours a week playing video games were classified as "heavy gamers." Of the 342 students on academic probation in the study, 127 were found to be heavy gamers.
Please use this information to answer the next three questions.
Calculate the point estimate p of the proportion of students on academic probation that are heavy gamers.
Referring to the previous question, consider the distribution of all sample proportions p^ when the sample size is 342. Calculate the mean and standard deviation of this distribution, assuming that p=0.4
Input your answers in the next two questions.
The mean is 0.4
Your Answer:
The standard deviation is 0.0265
Your Answer:
Sd = sqrt( p*(1-p)/n) = sqrt(0.4*0.6/342) = 0.0265
The means of the differences are not 0.
All three of the population means are different from each other.
Answer: At least one of the population means is different from at least one other.
Ha:optimisticneutralpessimistic
Which of the following are requirements that the psychologists would have to satisfy, to justify completing their ANOVA test? Mark all that apply.
The largest standard deviation for the three samples has to be less than four times the smallest.
The largest variance for the three samples has to be less than four times the smallest.
The samples need to carefully matched to each other, as in a paired-data test.
The three populations (healing times for each of the three groups) need to be normal.
There must be at least 30 people in the study, all together.
There must be at least 30 people in each sample.
A study examined possible reasons for students going on academic probation. Students who spent more than 20 hours a week playing video games were classified as "heavy gamers." Of the 342 students on academic probation in the study, 127 were found to be heavy gamers.
Please use this information to answer the next three questions.
Calculate the point estimate p of the proportion of students on academic probation that are heavy gamers.
Referring to the previous question, consider the distribution of all sample proportions p^ when the sample size is 342. Calculate the mean and standard deviation of this distribution, assuming that p=0.4
Input your answers in the next two questions.
The mean is 0.4
Your Answer:
The standard deviation is 0.0265
Your Answer:
Sd = sqrt( p*(1-p)/n) = sqrt(0.4*0.6/342) = 0.0265