We have been given that the standard deviation of a group of 20 scores is 15 and we are asked to find variance.
Since we know variance is square of standard deviation. In order to find out the variance of the given data we have to take the square of 15.

Therefore, our variance is 225.
Answer:
B. List each book on a separate piece of paper, place them all in a hat, and pick three
D. Number the books from 1 to 9 and use a random number table to produce 3 different one digit numbers corresponding to the books selected
Step-by-step explanation:
A simple random sample is a subset of a statistical population where every member has an equal chance of being selected.For example in a company with 500 workers, names of 100 workers can be selected from a hat containing the names of 500 workers.
Answer:
see below
Step-by-step explanation:
The experimental probability of heads is
P( heads) = 28/50 = 14/25
The theoretical probability is
P (heads) =1/2
Getting a common denominator for the experimental
25/50
comparing the experimental and the theoretical
28/50 > 25/50
experimental > theoretical
Answer:
Step-by-step explanation:
It's an obtuse. A triangle is considered acute if all 3 angles are acute; it is considered obtuse if one of its angles is obtuse. Ours has a 100 degree angle, so it is obtuse.
Answer:
60 r 56
Step-by-step explanation: