Answer:
The answer is below
Step-by-step explanation:
a) For a normal model the sample size has to be equal or greater than 30 so that it can be a normal distribution.
b) Given that:
μ = 11.2 minutes, σ = 4.8 minutes, n = 45
The z score determines how many standard deviations the raw score is above or below the mean. It is given by:

For x < 10 minutes

Therefore from the normal distribution table, P(x < 10) = P(z < -1.68) = 0.0465
That is going to be 48 for the first question because 6x8 equals 48
Answer:
There were 39 children at the party
Step-by-step explanation:
Here, we want to know the number of children at the party
To do this, we have to add the y-values ( frequencies of the age grades)
We have this as;
8 + 8 + 7 +10 + 6 = 39