10.) If a random variable X has a normal distribution with mean 10 and standard deviation 5, the 25th percentile of the distribution of the random variable equals
0.2908
0.4432
0.5587
0.6276
0.7034
11.) If a random variable X has a normal distribution with mean 10 and standard deviation 5, the upper quartile (or the 75th percentile) of the distribution of the random variable equals
10.12
10.56
11.08
12.19
13.37
12.) If a random variable X has a normal distribution with mean 10 and standard deviation 5, the top 1% cutoff of the distribution of the random variable equals
21.63
20.45
20.18
19.88
19.25
13.) If X has a normal distribution with mean 10 and variance 4, Y has a normal distribution with mean 6 and variance 5, and the two random variables are independent, what is the distribution of X + Y?
Normal with mean 16 and variance 9
Normal with mean 16 and variance 3
Normal with mean 16 and variance 1
Normal with mean 4 and variance 3
None of these
14.) A random variable X is normal with mean 16 and variance 9. What is the z-score of x = 22?
0.5
1
2
2/3
None of these
15.) If X has a standard normal distribution, then the probability that X is greater than 0.28 equals
0.3512
0.3371
0.3652
0.3710
0.3897
16.) For any normal distribution random variable X, which of the following is wrong?
with chance around 68%, X falls within one standard deviation of the mean
with chance around 95%, X falls within two standard deviations of the mean
with chance around 99.7%, X falls within three standard deviations of the mean
All of the above are correct.
All of the above are wrong.