Answer :
That’s it, the probability of getting tail on a single coin toss times the number of observations.
In this case, 1/2 * 72 = 36
However, there’s something called chance error. How much do you expect the result to differ from the expected value? It can be calculated as follows:
The Standard Deviation of this experiment is √(0.5)(0.5) =0.5
The Standard Error is √72 (0.5) ≈ 4.18330 round to the nearst tenth is 4
So, the expected value is 36, give or take 4.
And since the number of tails in a toss coin experiment is normally distributed, then you can expect the number of tails to be between -2 and +2 SEs from the expected value 95% of the time.
In other words, if you repeat this experiment a large number of times, you can expect to obtain between 27 and 43 tails 95% of the time.
Hope this helps
This is a concept of combination, the question requires us to find out how many combinations of students a teacher can choose if she sends 3 of her student to pick up books for the class. Since there is no specific order in selection, the combination will be given by:
nCr
n=Total number of the sample
r=number of students o be selected
thus the combination will be:
18C3
=816
This implies that there are 816 ways in which the Ms Washington can select the students
