Help with statistics

[Tombo]

My girlfriend is at uni at the moment and has some statistics questions and she's struggling with a few of them, if anyone here is good with it would they mind explaining it too, I think that might help.

2. A study of therapy effectiveness on substance abuse had the experimental group undergo therapy with a general psychodynamic approach administered by Dr. Carmen, while the other group participated in therapy with a general CBT approach administered by Dr. Johns.
What is the confound in this study?


a. The type of therapy
b. The therapy effectiveness of substance abuse
c. The experimental group
d. The doctor administering the therapy.
e. There is no confound in this study

10. A test for selecting intellectually gifted children has a population mean of 56 and a standard deviation of 8. You measure 64 children and obtain a sample mean of 57.28. In what percent of the top scores is this sample mean?

a. Top 3% of means
b. Top 5%
c. Top 8%
d. Top 10 %
e. None of the above

12. 15 students take a psychology quiz, and the mean score is calculated as 8 and the standard deviation is 1.6. The sum of raw scores must be;

a. 90
b. 60
c. 110
d. 120
e. Not enough information provided

13. How many of the raw scores in a distribution made up of 200 raw scores will fall between the 40th and 42nd percentile?

a. 2
b. 5
c. 15
d. 4
e. None of the above.

14. A researcher is conducting a study to determine how exercise affects depression levels in university students in Australia. In her study, what would be the dependent variable?

a. depression levels
b. exercise
c. both exercise and depression levels
d. university students

8. A recent graduate has two job offers and must decide which to accept. The job in City A pays $27,000. The average cost of living there is $50,000, with a standard deviation of $15,000. The job in City B pays $12,000. The average cost of living there is $14,000, with a standard deviation of $1000. Assuming the data are normally distributed, which is the better job offer?

a. Job A is better than Job B
b. Job A and Job B are the same
c. Job B is better than Job A
d. There is not enough information.

For the last one she thinks Job A at the moment.

Had to post this or receive constant nagging

 

[Participant]

For the first one, I'd say the confound is the doctor, as the change of doctor is confounding the attempt to link the types of therapy to the causal effect of the therapy. In other words, ideally the same doctor would do both trials.

 

[Viper²]

Divorce.

 

[Tombo]

Tempting

For the first one she seems to think it's the experimental group, because how can you attribute the effectiveness purely on therapy when people in the groups could have different values like willingness to change and pre-knowledge? ? I have no clue