Need answers and explanation, six step hypothesis test with Minitab 2 Goodness of Fit Test along with Minitab instructions

A psychologist believes that a certain type of counseling will have a positive effect on 60% of the persons being counseled, no effect on 25% of the patients, and a negative effect on 5% of the patients. The psychologist then counsels 50 patients with this method, 25 realize positive effects, 20 realize no effect, and 5 realize a negative effect. Test whether the distribution that the psychologist originally beleived to be true was, in fact, supported by her sampling. Use 5% siginificant level.