The volleyball coach at a large high school wants to estimate the number of times players spike the ball during any given game. She randomly selects 30 games and records the number of spikes. The coach constructs a 95%
confidence interval for the true mean number of spikes players make in a game. Which of the following would
decrease the margin of error?
O using a sample of size 15
O using a sample of size 25
constructing a 90% confidence interval
constructing a 99% confidence interval

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.