Question

the mean monthly income of trainees at a local mill is 1100 with a standard deviation of 150. find rthe probability that a trainee earns less than 900 a month g

Answer 1

Answer:

The  probability is  $P(X < 900 ) = 0.0918$

Step-by-step explanation:

From the question we are told that

   The sample mean is  $\= x = 1100$

    The  standard deviation is  $\sigma = 150$

     The random number value is  x =900

The probability that a trainee earn less than 900 a month is mathematically represented as

       $P(X < x) = P(\frac{X -\= x}{\sigma} < \frac{x -\= x}{\sigma} )$

Generally the z-value for the normal distribution is mathematically represented as

       $z = \frac{x -\mu }{\sigma }$

So From above we have

      $P(X < 900 ) = P(Z < \frac{900 -1100}{150} )$

      $P(X < 900 ) = P( Z$

Now from the z-table

    $P(X < 900 ) = 0.0918$