What is the value of mew in a standard normal distribution?

What is the value of the standard devation in a standard normal distribution?

ind the area of the standard normal distribution that lies to the left of Z = −1.50.

The mean for the standard normal distribution is ____.

In a distribution exactly normal with mean 47.5 Kilogram, 89.97% of the items are under 70 kilogram weight. Then which of the following is the standard deviation of the distribution? Given that area under standard normal curve from Z=0 to Z=1.28 is 0.3997.

Z is a standard normal random variable. The P(-1.5 < Z < 1.19)  A. 0.7953 B. 0.0711 C. 0.3621 D. 0.8162