Maths statistics

QUETION Al [4 marks) A study among 120 random teenagers who enter the cinema found that 35% of them are using their phones for more than a minute while watching the movie. Find, (a) the mean number of teenagers who use their phones for more than a minute. (2 marks) (b) the standard deviation number of teenagers who use their phones for more than a minute. (2 marks) QUESTION A2 [4 marks! A volunteer sells cookies to raise money for an old folk home to support their utilities. The probability that he successfully sells the cookies is 30%. Determine the probability that if he approaches 15 people at random, he will sell the cookies to, (a) exactly 7 people (1 mark) (b) at least 2 people (3 marks) QUESTION A3 [4 marks! A botanist studied the viability of the seed accession at random. The average number of seeds alive varies for each day. On Sunday, there is a constant average of 2 alive seeds per minute. Calculate the probability of alive seeds at a maximum of 3 per minute