The average score on a standardized test is 750 points with a standard deviation of 50 points. If 2,000 students take the test at a local school, how many students do you expect to score between 700 and 800 points?

1130

1200

1360

1500

Question

The average score on a standardized test is 750 points with a standard deviation of 50 points. If 2,000 students take the test at a local school, how many students do you expect to score between 700 and 800 points?

		
1130
 		
1200
 		
1360
 		
1500

anonymous · Answer

The average score on a standardized test is 750 points with a standard deviation of 50 points. If 2,000 students take the test at a local school, how many students do you expect to score between 700 and 750 points?
Answer
	a. 	
720
	b. 	
680
	c. 	
740
	d. 	
700

paxpolaris · Answer

http://upload.wikimedia.org/wikipedia/commons/8/8c/Standard_deviation_diagram.svg

paxpolaris · Answer

1st question : 68% of 2000

1st question : 34% of 2000

anonymous · Answer

thank you paxpolaris :)

paxpolaris · Answer

sorry thats 
2nd question : 34% of 2000

anonymous · Answer

The time required to finish a test in normally distributed with a mean of 40 minutes and a standard deviation of 8 minutes. What is the probability that a student chosen at random will finish the test in more than 48 minutes?  does it have a formula or something cuz i got like 5 more like this.

paxpolaris · Answer

i would use z-table to answer such a question

anonymous · Answer

oh no clue what that is but i will look it up .thanks again :)

paxpolaris · Answer

sorry... no need for Z-table

All you need is the link to graph I posted above.

paxpolaris · Answer

48= 40+ 8 .... so you have 34.1% between 40 & 48

and 50% above 40

so above 48 you have: 50-34.1 = 15.9%

paxpolaris · Answer

do you get that @justightful

anonymous · Answer

i am sorry lol and yes I got it .your so help full :)