A manufacturer makes two sizes of elastic bands: large and small. 40% of the bands produced are large bands and 60% are small bands. Assuming that each pack of these elastic bands contains a random selection, calculate the probability that, in a pack containing 20 bands, there are
A survey of adults in a certain large town found that 76% of people wore a watch on their left wrist, 15% wore a watch on their right wrist and 9% did not wear a watch.
A random sample of 14 adults was taken. Find the probability that more than 2 adults did not wear a watch.
(i) State two conditions which must be satisfied for a situation to be modelled by a binomial distribution.
In a certain village 28% of all cars are made by Ford.
(ii) 14 cars are chosen randomly in this village. Find the probability that fewer than 4 of these cars are made by Ford.
A shop sells old video tapes, of which 1 in 5 on average are known to be damaged.
A random sample of 15 tapes is taken. Find the probability that at most 2 are damaged.
Single cards, chosen at random, are given away with bars of chocolate. Each card shows a picture of one of 20 different football players. Richard needs just one picture to complete his collection. He buys 5 bars of chocolate and looks at all the pictures. Find the probability that