# Stat questions: Help

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1. ### OP angry hiccups Newbie Newcomer Level 1

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Help me with some study questions guys;

1. 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

2. 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.

3. 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

4. 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

2. ### alphenor Advanced Member Newcomer Level 1

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I didn't answer # 1 since I don't understand the question...
I'm not sure about #3 since I'm not also sure what meaning of confound is used.

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4. ### alphenor Advanced Member Newcomer Level 1

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Don't get confused with the question. It talks about 57.28, and I didn't answer coz the "top scores" are suddenly mentioned.....

(a little while)..
w8...i think I get the question now.. the probability of scores less than the sample mean is .5636 (based on the z-table..subtracted the pop mean from the sample mean and divided the answer by the standard dev)...so, by that, the items higher than 57.28 is 1 - .5636 = .4364...which goes to E...

but the problem is...the 1st choice. It says "Top 3% of means".

Is this a question exactly based from a reliable source, or the one at the top of this thread just made it by himself?
I placed this question coz there's something wrong with #1.. (I think).

5. ### Linkiboy GBAtemp Testing Area Member Level 6

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The confound is the doctor administering the survey

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