Thursday

January 29, 2015

January 29, 2015

Posted by **Joanne** on Monday, August 4, 2008 at 9:17pm.

a. Find the probability that a randomly selected student's score on the English part of the SAT is between 400 and 675.

b. What is the minimum SAT score that a student can receive in order to score in the top 10%?

c. Forty-nine students are sampled. Find the probability that their mean score for the SAT is less than 470.

I have the following answers, but do not know how they were derived:

a. 0.8013

b. 628

c. 0.0179

- statistics -
**MathGuru**, Monday, August 4, 2008 at 9:47pmHere's a few hints to get you started:

a. Find the z-scores. Use the formula: z = (x - mean)/sd

z = (400 - 500)/100 = ?

z = (675 - 500)/100 = ?

Once you have the two z-scores, look at the z-table to determine the probability between those two scores.

b. Check the z-table to determine the top 10%. Use that value for z. Use the z-score formula. You will have z, the mean, and the standard deviation. Solve the formula for x.

c. Formula: z = (x - mean)/(sd/√n)

With your data:

z = (470 - 500)/(100/√49) = ?

Once you have the z-score, check the z-table for the probability. Remember that this problem is looking for "less than" 470, so keep that in mind when looking at the table.

I hope this will help.

- Thank you -
**Joanne**, Monday, August 4, 2008 at 11:14pmPerfect advice. I appreciate the help!

**Answer this Question**

**Related Questions**

statistics - Suppose that SAT scores among U.S. college students are normally ...

math - The distriubution of the SAT scores in math for an incoming class of ...

Math Helppp - Scores for men on the verbal portion of the SAT-I test are ...

Finite math - Scores for men on the verbal portion of the SAT-I test are ...

statistics - Scores for men on the verbal portion of the SAT-1 test are normally...

statistics - Suppose scores on the mathematics section of the SAT follow a ...

Math (Statistics) - The SAT scores of a certain population of students are ...

statistics - Suppose scores on the mathematics section of the SAT follow a ...

statistics - SAT I scores around the nation tend to have a mean scale score ...

Statistics - SAT I scores around the nation tend to have a mean scale score ...