Please Help Me! Multiple Choice!

Question

anonymous · Answer

with what?

anonymous · Answer

For exercises 1 and 2, a set of data has a normal distribution with a mean of 120 and a standard deviation of 10.

1. Find the interval about the mean within which 90% of the data lie.
a. 94.2-145.8
b. 103.5-136.5
c. 113.68-126.32
d. 100.4-139.6

anonymous · Answer

2. Find the probability that a value selected at random from this data is between 100 and 140.
a. 99.9%
b. 90%
c. 99%
95.5%

anonymous · Answer

@Blank  @girlnotonfire @Destinymasha

anonymous · Answer

@iPwnBunnies @jim_thompson5910 @ganeshie8 @mathstudent55 @dan815

anonymous · Answer

@GeraldJRJunior

anonymous · Answer

@bloopman @shamim

jim_thompson5910 · Answer

use a table like this one http://3.bp.blogspot.com/_5u1UHojRiJk/TEdJJc6of2I/AAAAAAAAAIE/Ai0MW5VgIhg/s1600/t-table.jpg to find the z score that corresponds to a 90% level

jim_thompson5910 · Answer

tell me what z score you get

anonymous · Answer

Im sorry. I dont understand, can you explain?

jim_thompson5910 · Answer

see the row that starts with infinity?

anonymous · Answer

yes

jim_thompson5910 · Answer

which value is above 90%

anonymous · Answer

1.645?

anonymous · Answer

@jim_thompson5910

jim_thompson5910 · Answer

that means 

P( -1.645 < z < 1.645 ) = 0.90

jim_thompson5910 · Answer

Basically, we have this normal distribution

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