8. The average IQ of adult population is 100 and are normally distributed. A researcher believes the IQ of adults is lower. A random sample of 15 adults are tested and scored: 72, 102, 92, 65, 84, 75, 78, 104, 69 ,79 , 89 , 99 , 109, 98, 81 Use a significance level of 0.05. 9. The average IQ for the adult population is 100 with a standard deviation of 15. A researcher believes this value has changed. The researcher decides to test the IQ of 92 random adults. The average IQ of the sample is 98. Is there enough evidence to suggest the average IQ has changed? 10. For this example, we will assume that for a typical flight, the probability of a hydraulic system failure is 0.002. a. If the Airbus 310 were to have one hydraulic system, what is the probability that the aircraft's flight control would work for a flight? b. Given that the Airbus 310 actually has three independent hydraulic systems, what is the probability that on a typical flight, control can be maintained with a working hydraulic system