document.write( "Question 905056: Given a normal distribution with u=100 and q=10, if you select a sample of n=25, what is the probability that x bar is:
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Algebra.Com's Answer #548993 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!

 
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document.write( "Hi
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document.write( "really recommend us TI Calculator. 
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document.write( "However, z values are easy enough manually, and then going to Excel NORMSDIST(z)  
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document.write( "a. less than 95: P(z < (95-100)/10/sqrt(25) = P(z < -5/2) =NORMSDIST(-2.5)= .0062 
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document.write( "b. between 95 and 97.5: P(z< -1.25 - P(z< -2.5)= .1057 -.0062
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document.write( "TI ,makes this so easy) normalcdf(-2.5, -1.25)
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document.write( "c. above 102.2 = 1 -P(z < 1.1)= 1- .8643\r
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document.write( "d. there is a 65% chance that Xbar is above what value X? 
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document.write( "invNorm(.45) Or Excel NORMSINV(.45)= -.1257 = z
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document.write( "-.1257 = (X-100)/10/sqrt(25)
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document.write( "2(-.1257) + 100 = X  \n" );
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