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Mortars used in most modern buildings are made using cement. a student tested the strenght of a ready mixed mortar. he did this by dropping a mass onto a small mortar beam from increasing heights until the beam broke in half.he tested 4 beams made from mortar.his results were 20cm, 50cm , 65cm and 15 cm. a) what was the range of the students results? 15cm-65cm am i right? b)work out the mean of these results. can remember what mean is. do you have to add them all then divide them by how many there are? c)comment on the precision of his results. stuck d) besides cement what was the other solid in the ready mixed mortar? what other solid is needed to make concrete instead of mortar? help me.

A) take 15 for 65 - the range is 50cm. b) the mean is indeed (20+50+65+15) divided by 4. so the mean is 37.5cm. c) were the intervals he used close enough together to find the breaking point exactly? not . d) sand e) gravel hope this helps