How do I find for the defree of freedom Please explain in de

How do I find for the defree of freedom. Please explain in details and step by step.

The American Airlines flights would like to study the departure delay time. They would like to test the claim that the mean departure delay time for all flights from New York to Los Angeles is less than 12 min. They recorded 64 different departure delay times and found the mean is 10 min and the standard deviation is 30 min. Use a 0.01 significance level to test the claim. 3. what is the degree of freedom?

a) 30 b) 64 c) 63 Incorrect Response d) 8

Solution

degrees of freedom=total number of observations-no. of linear paramaters estimated.

now here total number of observations=64

from the question it is not clear whether the mentioned standard deviation is that of the population or of the sample.

if the standard deviation is of the sample then the population standard deviation is estimated by this sample Standard deviation. so then the degrees of freedom would be 64-1=63

but if it is the population standard deviation itself then there is no need of estimation. then the degrees of freedom would be 64-0=64

as in the question it is given that 63 is the incorrect response. then it is clear that the standard deviation is the population standard deviation. hence the degrees of freedom is 64 [answer]