Applicants to a psychology department have normally distributed GRE scores with a mean, LaTeX: \muμ, of 544 and a standard deviation, LaTeX: \sigmaÏ, of 103. What percentage of applicants scored between 500 and 700? Round to the nearest percent.A. -24% B. 78% C. 2296 D. 24% E. 5%

Respuesta :

Answer:

The probability is P(500 < X  < 700 ) =  0.60044

Step-by-step explanation:

From the question we are told that

    The mean is  [tex]\mu = 544[/tex]

     The standard deviation is  [tex]\sigma = 103[/tex]

Generally the percentage of applicant that scored between 500 and 700 is mathematically represented as

      [tex]P(500 < X < 700 ) = P(\frac{500 - 544}{103} < \frac{X - \mu }{\sigma } < \frac{700 - 544}{103} )[/tex]

[tex]\frac{X -\mu}{\sigma }  =  Z (The  \ standardized \  value\  of  \ X )[/tex]

      [tex]P(500 < X < 700 ) = P(-0.4272 < Z < 1.5146 )[/tex]

=>   [tex]P(500 < X < 700 ) = P( Z< 1.5146 ) - P ( Z < -0.4272 )[/tex]

Generally from the z-table, the area under the normal curve to the left corresponding to    1.5146 and     -0.4272  is

  P(  Z<  1.5146 )  =  0.93506

   P ( Z <   -0.4272 ) = 0.33462

So

       P(500 < X  < 700 ) =  0.93506 -  0.33462

=>    P(500 < X  < 700 ) =  0.60044