QUESTION 7 Which of the following is always true for any normal distribution? The standard deviation is equal to 1. The

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QUESTION 7
Which of the following is always true
for any normal distribution?
The standard deviation is equal to 1.
The curve is symmetric around 0.
The total area under the normal distribution curve between μ –
2σ and μ + 2σ is about 0.95.
The normal distribution is completely defined by its
mean, μ, and sample size, n.
QUESTION 9
Your research firm has found that salaries for retail cashiers
have a normal distribution with a mean of $15,726 per year and a
standard deviation of $1,388. Find the probability that a randomly
selected retail cashier has a salary greater than $16,768.
0.9587
0.8095
0.9525
0.2266
0.7734
QUESTION 22
If Z is a standard normal random variable, find P(-1.96 < Z
< 1.96)
0.90
0.95
0.975
0.025
0.997
Please help me to solve these questions!