Answer:
a. Yes(n=500>=5, n(1-p)=25>=5)
b. 0.15241
Step-by-step explanation:
a. A normal approximation to the binomial can be used
5 and n(1-p)>=5:
#We calculate our p as follows:
=x/n=470/500=0.94
n=500
n(1-p)=500(1-0.95)=25
Hence, we can use the normal approximation.
b. This is a normal approximation.
-Given that p=0.95(95%)
-We verify if our distribution can be approximated to a normal:

Hence, we can use the normal approximation of the form:

Hence, the probability of the sample proportion is the same as the proportion of the sample found is 0.15241
3/4 = 6/x....3/4 = 6/8...notice that proportions are nothing but equivalent fractions
x = 8
Using the given formula T = LS
And given the time is 3 minutes (3 x 60 = 180 seconds)and the speed is 4-1/2 inches per second:
180 = L x 4-1/2
Solve for L by dividing both sides by 4-1/2:
L = 180 / 4-1/2
L = 40
The length should be 40 inches.