a survey found that the american family generates an average of 17.2 pds of glass garbage each year. Assume the standard deviation of the distribution is 2.5 pds. Find the probability that the mean of a sample of 55 families will be between 17 and 18 pds.
z1= 17-17.2 = .8 = 2.37=(in the chart it says .9911)
2.5/sqrt 55 .337
z2= 18-17.2 = -.2 = -.59 (in chart it says .2276)
2.5/sqrt55 .337
so i do .9911-.2276=.7635
i kow this is wrong, my book doesn't show an example like this. That is how i do best, following an example until I get it down. Can someone work this out step by step please so I can see and follow? thank you in advance!
z1= 17-17.2 = .8 = 2.37=(in the chart it says .9911)
2.5/sqrt 55 .337
z2= 18-17.2 = -.2 = -.59 (in chart it says .2276)
2.5/sqrt55 .337
so i do .9911-.2276=.7635
i kow this is wrong, my book doesn't show an example like this. That is how i do best, following an example until I get it down. Can someone work this out step by step please so I can see and follow? thank you in advance!