Jamaal decides to select a sample of the population at his school to survey in order to determine the most watched show on TV. He divides the school population into males and females, and into grades.
He then sends 5 male survey forms and 5 female survey forms to each homeroom in the school to collect his information.
What type of sampling technique is Jamaal using?
Identify any bias that may exist in his sampling technique?
Suggest possible ways of reducing this bias.

An engineer is going to redesign an ejection seat for an airplane. the seat was designed for pilots weighing between 120 lb and 161 lb. the new population of pilots has normally distributed weights with a mean of 125 lb and a standard deviation of 28.1 lb. a)if a pilot is randomly selected, find the probability that his weight is between 120 lb and 161 lb.the probability is approximately? b. if 36 different pilots are randomly selected, find the probability that their mean weight is between 120 lb and 161 lb. the probability is approximately? c. when redesigning the ejection seat, which probability is more relevant? . part (b) because the seat performance for a single pilot is more important. b. part (b) because the seat performance for a sample of pilots is more important. c. part (a) because the seat performance for a sample of pilots is more important. d. part (a) because the seat performance for a single pilot is more important.