I need a step by step solution to this: (The answers are already given; I just need the computations) Data indicates an average population weight of a fish of 40 lbs and a standard deviation of 4 lbs. Assume weight is normally distributed in the population. How probable was it to catch a tuna:...

well I need help... I have tried many times but can't figure this one out. The waist measurement of students in a college is normally distributed. The standard deviation is known to be 5 inches. It is found that 15% of the students have waist sizes less than 28 inches. What proportion of...

its about a manufacturer performing a test on its calculators and finds their work life to be normally distributed. OK if I have a mean u=2150 hours and a standard deviation of 450 hours. What should be advertised as the life of the calculators so that 90% of the calculators are covered ? a.2,555...

Suppose that a student's verbal score X can be considered an observation from normal distribution having mean 500 and standard deviation 80. a) Find P(X>660) b) Find the 90 percentile of the distribution c) Find the probability that the student scores below 420 d) Find the probability that the...

I don't understand this whole Z curve stuff could someone explain it to me and help with this example question Find the area under the Z curve corresponding to the each of the z values described below. your answer should be accurate to at least four decimal places. A) less than -0.61 B)...