Answer:
1/5
Step-by-step explanation:
You expect to get 12 red marbles out of 60 trials.
So, you expect to get a red marbles 12/60 of the times.
We can simplify that 12/60 to 1/5, which is a choice of answers. :-)
We assume here you correctly assume your probability level when you did your forecast of 12/60. And either you're picking from a small pool and re-insert the marble, or you have a very large amount of marbles (at least 60).
Your calculator says error because you cant have a square root of a negative number because there is no solution to that maybe recheck your equation and try again
Answer=45minutes
three quarters= 3/4 or 75%
an hour is 60 minutes
3/4*60minutes=45minutes
Answer:
Since we can't assume that the distribution of X is the normal then we need to apply the central limit theorem in order to approximate the
with a normal distribution. And we need to check if n>30 since we need a sample size large as possible to assume this.

Based on this rule we can conclude:
a. n = 14 b. n = 19 c. n = 45 d. n = 55 e. n = 110 f. n = 440
Only for c. n = 45 d. n = 55 e. n = 110 f. n = 440 we can ensure that we can apply the normal approximation for the sample mean
for n=14 or n =19 since the sample size is <30 we don't have enough evidence to conclude that the sample mean is normally distributed
Step-by-step explanation:
For this case we know that for a random variable X we have the following parameters given:

Since we can't assume that the distribution of X is the normal then we need to apply the central limit theorem in order to approximate the
with a normal distribution. And we need to check if n>30 since we need a sample size large as possible to assume this.

Based on this rule we can conclude:
a. n = 14 b. n = 19 c. n = 45 d. n = 55 e. n = 110 f. n = 440
Only for c. n = 45 d. n = 55 e. n = 110 f. n = 440 we can ensure that we can apply the normal approximation for the sample mean
for n=14 or n =19 since the sample size is <30 we don't have enough evidence to conclude that the sample mean is normally distributed