# Statistics

I know don't know if this right P(X)<115)= 12.1 (115-mean) how do I get the mean or is there a formula that can help me solve this?

A population of line voltages has a standard deviation of 1.20 volts. What value would the mean line voltage have to be so that 12.1% of the line voltages fell below 115V?

1. Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.121) and its Z score. Z score = -1.27 is standard deviations below the mean.

115 + 1.27(1.2) = mean

posted by PsyDAG

## Similar Questions

1. ### science

The flowerpot weighs 5 pounds on Earth and 0.29 pounds on Pluto. Which proportion could you use to calculate a 115-pound personâ€™s weight on Pluto? A. 5 over 0.29 = 115 over w B. 0.29 over 5 = w over 115 C. 5 over 0.29 = w over
2. ### complex number ~

thanks BOB =) *HUGS* 115 cis 45* 3 solutions = 120* apart Are these correct? 115 cis 45* 115 cis 45 + 120 = 165* or is it (-75*) 115 cis (45 + 120 + 120) = 285*?? or (-195*)?? It's really Matthew!I found out what it is but I will
3. ### MATH

Sally is evaluating some test papers. There are 80 multiple choice questions in the test. Students get two points for every correct answer and for every wrong answer or any question left blank, one point is deducted from the total
4. ### complex numbers

115 cis 45* 3 solutions = 120* apart Are these correct? 115 cis 45* 115 cis 45 + 120 = 165* 115 cis (45 + 120 + 120) = 285*?? WHat is cis? cos + isin OH LOL!!!Wish I could help!LOL!But...PLease help me!!:(
5. ### Algebra

Can you please help me solve: Fifteen less than twice some number is 115. 15 - 2x = 115 is this the correct equation? thank you
6. ### math help!

bernardo folds the 2 top corners of a rectanglular piece of paper to form 2 conguent triangles and an isosceles trapezoid. The triangles each have an angle that measures 65. what are the measures of the 2 top angles in the
7. ### Statistics

A student wants to test her hypothesis she gives each of her students an IO test. She finds that the average IQ score is 115 and the standard deviation for the class is 30. There are 22 students in the class. She also knows that
8. ### geometry

I found out the first part of which is x for the figure which was 115 degrees.They do give you the other measures of the angles which are 115,155,155,155.135,135,115.The second part of the problem say yo find the sum of the
9. ### math

115-100+3*5= 115-100+3*5...Use BEDMAS (Bracket, Exponent, Division/Multiplication, Addition/Subtraction). So you would first do 3*5 which is 15. So you'd have: 115-100+15 And then from there solve to get 30. It's PEMDAS Raj!! P -
10. ### Henry ford academy elemetry

Write 115,234 in expanded form and in written form 115+200+30+20

More Similar Questions