Acompany manufactures tennis balls. when its tennis balls are dropped onto a concrete surface from a height of 100 inches, the company wants the mean height the balls bounce upward to be 55.4 inches. this average is maintained by periodically testing random samples of 25 tennis balls. if the t-value falls between minus−t 0.90 and t 0.90, then the company will be satisfied that it is manufacturing acceptable tennis balls. a sample of 25 balls is randomly selected and tested. the mean bounce height of the sample is 56.6 inches and the standard deviation is 0.25 inch. assume the bounce heights are approximately normally distributed.
is the company making acceptable tennis balls?

Exercise: counting committees 0.0/2.0 puntos (calificable) we start with a pool of n people. a chaired committee consists of k≥1 members, out of whom one member is designated as the chairperson. the expression k(nk) can be interpreted as the number of possible chaired committees with k members. this is because we have (nk) choices for the k members, and once the members are chosen, there are then k choices for the chairperson. thus, c=∑k=1nk(nk) is the total number of possible chaired committees of any size. find the value of c (as a function of n ) by thinking about a different way of forming a chaired committee: first choose the chairperson, then choose the other members of the committee. the answer is of the form c=(α+nβ)2γn+δ. what are the values of α , β , γ , and δ ?