Accordingto statistics released by the Department of Civil Aviation, the average delayof flights is equal to 16.8 minutes, flight delays are assumed to follow anormal distribution.  However, from asample of 50 flights, the average delay was estimated to be 19.5 minutes andthe sample standard deviation was 6.6 minutes.Conducta hypothesis test to disprove the claim that the average delay is equal to 16.8minutes at a= 0.01.

In 2020, 16.9% flights arriving to LAX were 15 minutes or more late. Theaverage “arriving late” time was 11.93 minutes per flight. Investigators want tosee whether the delay times have changed since 2020.The available data set from 2021 shows 10 randomly selected airlines and theirarrival information for each month.SHOW YOUR WORK FOR EACH QUESTION!1. First you need to investigate whether the proportion of late flights has changed from 16.9%.a. Write the null and alternative hypotheses.

The manager of a grocery store has taken a random sample of 100 customers to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. She observes that the average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minutes.

Researchers simulated boarding times for airline passengers using the normal distribution. They created different statistical models by varying the boarding strategies used, the amount of luggage passengers had, the capacity of the plane, how full the flight was, and the layout of the seats on the plane. One of the normal distribution models used for boarding times had a mean of 6.9 minutes and a standard deviation of 1.5 minutes. Use the normal distribution explorer app in our course book (under the Tools section) to answer the following questions. There may be some slight differences in answers between the tool and this quiz, so choose the answers closest to what the tool provides. Using the normal distribution model defined above: the middle 95% of boarding times are modelled to be between around [ Select ] and [ Select ] minutes. A boarding time of 8 minutes would be [ Select ] , as it has a [ Select ] tail proportion of around [ Select ] . Another boarding time of 5.3 minutes would be [ Select ] unusual than the first boarding time of 8, as its tail proportion is [ Select ] . If the model was changed, and the standard deviation was bigger, the middle 95% of boarding times under this model would become a [ Select ] interval.

In a flight of 600 km, an aircraft was slowed down due to bad weather. Its average speed for the trip was reduced by 200 km/hr and the time of flight increased by 30 minutes. The duration of the flight is:1 hour

Internet connections are often slowed by delays at nodes. Let us determine if the delay time increases during heavy-volume times. Four hundred packets are sent through the same network between 5 pm and 6 pm (sample X ), and four hundred packets are sent between 10 pm and 11 pm (sample Y ). The early sample has a mean delay time of 0.7 sec with a standard deviation of 0.11 sec whereas the second sample has a mean delay time of 0.6 sec with a standard deviation of 0.09 sec.Construct a 99.5% confidence interval for the difference between the mean delay times.