Question 3
For his Statistics class project, researcher J. Gilbert decided to study how parents’ income affects children’s performance on standardized tests like the SAT. He proposed to collect information from a random sample of test takers and examine the relationship between parental income and SAT score.
a) What is the population of interest?
children who take standardized tests
Coffee stations in offices often just ask users to leave money in a tray to pay for their coffee, but many people cheat. Researchers at Newcastle University replaced the picture of flowers on the wall behind the coffee station with a picture of staring eyes. They found that the average contribution increased significantly above the well-established standard when people felt they were being watched, even though the eyes were patently not real. (NY Times 12/10/06)
a)Which is the explanatory variable?
staring eyes/feeling like you are being watched
6) Over a 4-month period, among 30 people with bipolar disorder, patients who were given a high dose (10 g/day) of omega-3 fats from fish oil improved more than those given a placebo. (Archives of General Psychiatry 56 [1999]: 407)6)
a) What are the variables? Identify if they are categorical or quantitative.
taking fish oil or not: C
improving vs not improving: C
7) Among a group of disabled women aged 65 and older who were tracked for several years, those who had a vitamin B12 deficiency were twice as likely to suffer severe depression as those who did not. (American Journal of Psychiatry 157 [2000]: 715)
a) What are the variables? Identify if they are categorical or quantitative.
B12 deficiency - C
having severe depression - C
8) In a test of roughly 200 men and women, those with moderately high blood pressure (averaging 164/89 mm Hg) did worse on tests of memory and reaction time than those with normal blood pressure. (Hypertension 36 [2000]: 1079)
a) What are the variables? Identify if they are categorical or quantitative.
having moderately high blood pressure: C
memory & reaction time test scores:Q
For his Statistics class project, researcher J. Gilbert decided to study how parents’ income affects children’s performance on standardized tests like the SAT. He proposed to collect information from a random sample of test takers and examine the relationship between parental income and SAT score.
b) What are the variables? Identify if they are categorical or quantitative.
1) parents income: Q
2) SAT score: Q
Coffee stations in offices often just ask users to leave money in a tray to pay for their coffee, but many people cheat. Researchers at Newcastle University replaced the picture of flowers on the wall behind the coffee station with a picture of staring eyes. They found that the average contribution increased significantly above the well-established standard when people felt they were being watched, even though the eyes were patently not real. (NY Times 12/10/06)
b) Which is the response variable?
how much money people left for their coffee
6) Over a 4-month period, among 30 people with bipolar disorder, patients who were given a high dose (10 g/day) of omega-3 fats from fish oil improved more than those given a placebo. (Archives of General Psychiatry 56 [1999]: 407)b)
Is this statistical study, observational or experimental? Explain.
experimental- taking fish oil is a treatment
7) Among a group of disabled women aged 65 and older who were tracked for several years, those who had a vitamin B12 deficiency were twice as likely to suffer severe depression as those who did not. (American Journal of Psychiatry 157 [2000]: 715)
b) Is this statistical study, observational or experimental? Explain.
observation - no treatments
8) In a test of roughly 200 men and women, those with moderately high blood pressure (averaging 164/89 mm Hg) did worse on tests of memory and reaction time than those with normal blood pressure. (Hypertension 36 [2000]: 1079)
b) Is this statistical study, observational or experimental? Explain.
observation- no treatment was applied
For his Statistics class project, researcher J. Gilbert decided to study how parents’ income affects children’s performance on standardized tests like the SAT. He proposed to collect information from a random sample of test takers and examine the relationship between parental income and SAT score.
c) Explain which variable you think is the explanatory variable.
parents income is the explanatory variable because it may influence the child's SAT score
Coffee stations in offices often just ask users to leave money in a tray to pay for their coffee, but many people cheat. Researchers at Newcastle University replaced the picture of flowers on the wall behind the coffee station with a picture of staring eyes. They found that the average contribution increased significantly above the well-established standard when people felt they were being watched, even though the eyes were patently not real. (NY Times 12/10/06)
c) Is this statistical study, observational or experimental? Explain.
experimental - there was a treatment
6) Over a 4-month period, among 30 people with bipolar disorder, patients who were given a high dose (10 g/day) of omega-3 fats from fish oil improved more than those given a placebo. (Archives of General Psychiatry 56 [1999]: 407)
c) Write a conclusion appropriate for this type of study.
"This study shows that taking fish oil with omega-3 fats causes an improvement in Bipolar disorder"
7) Among a group of disabled women aged 65 and older who were tracked for several years, those who had a vitamin B12 deficiency were twice as likely to suffer severe depression as those who did not. (American Journal of Psychiatry 157 [2000]: 715)
c) Write a conclusion appropriate for this type of study.
This study suggests that a B12 deficiency may influence the likelihood of suffering from severe depression.
8) In a test of roughly 200 men and women, those with moderately high blood pressure (averaging 164/89 mm Hg) did worse on tests of memory and reaction time than those with normal blood pressure. (Hypertension 36 [2000]: 1079)
c) Write a conclusion appropriate for this type of study.
"This study may suggest that those with moderately high blood pressure perform worse on memory and reaction time tests."
For his Statistics class project, researcher J. Gilbert decided to study how parents’ income affects children’s performance on standardized tests like the SAT. He proposed to collect information from a random sample of test takers and examine the relationship between parental income and SAT score.
d) Is this statistical study, observational or experimental? Explain.
observational - no treatments were applied
Coffee stations in offices often just ask users to leave money in a tray to pay for their coffee, but many people cheat. Researchers at Newcastle University replaced the picture of flowers on the wall behind the coffee station with a picture of staring eyes. They found that the average contribution increased significantly above the well-established standard when people felt they were being watched, even though the eyes were patently not real. (NY Times 12/10/06)
d) Write a conclusion appropriate for this type of study that describes the relationship between the explanatory and response variables.
"The study shows that feeling like you are being watched causes people to donate more generously to the free will coffee donation."