An express mail service charges a special rate for any package that weighs less than 1 lb. Let x denote the weight of a randomly selected parcel that qualifies for this special rate. The probability distribution of x is specified by the density curve shown below. Use the fact that area of a trapezoid = (base)(average of two side lengths)to answer each of the following questions:
(a) What is the probability that a randomly selected package of this type weighs at most 0.4lb? between 0.35 and 0.5 lb? at least 0.85lb?
P(x≤0.4) =
P(0.35≤x≤0.5) =
P(x≥0.85) =
(b) It can be shown thatμx= 7/12 andσ2x= 11/144. What is the probability that the value ofxis more than 1 standard deviation from the mean value? (Round the answer to four decimal places.)
P(xis more than one standard deviation from the mean value) =