Answer:
Step-by-step explanation:
The question is incomplete because the data is missing, i.e. the probability that you will score 5, 4, 3, 2, 1.
But it is resolved as follows:
where m is the mean and sd is the standard deviation.
the m is calculated by the sum of the multiplication of the score by the probability of this
that is to say,
score probability
5 0.2
4 0.3
3 0.1
2 0.3
1 0.1
m = 5*0.2 + 4*0.3 + 3*0.1 + 2*0.3 + 1*0.1
m = 3.2
However, the standard deviation will be calculated by
sd = ∑
that is, knowing the mean already, we can calculate the standard deviation, following the example:
sd =
sd =
sd = 1.327
And also n = 5, because it's 5 scores. We replace in the initial equation:
Therefore for the example the number z is -0.337, which if in the normal distribution table corresponds to 0.3520, that is the probability that the average is at least 3, for the example is 35.20 %.