1. Data are from a normal distribution and the mean is 20 with a standard deviation of 2. a. What % of observations fall between 18 and 22

And we can find this probability with the normal standard distribution and we got:

Step-by-step explanation:

Let X the random variable that represent the variable of a population, and for this case we know the distribution for X is given by:

Where and

We are interested on this probability

And the best way to solve this problem is using the normal standard distribution and the z score given by:

Using this formula we got:

And we can find this probability with the normal standard distribution and we got:

spinning a 1, 2, or 3. option d.

step-by-step explanation: when spinning a number graph up to 4, and aiming for any number less than 3, that automatically eliminates the number 4. now you have two numbers to spin on that are less than 3, but the number 3 is included in this question because it's no greater of an number than itself. i hope this you : )