Answer:
First statement is correct.
Step-by-step explanation:
If we add or subtract a constant to each term in a set: Mean will increase or decrease by the same constant. Standard Deviation will not change.
If we increase or decrease each term in a set by the same percent (multiply all terms by the constant): Mean will increase or decrease by the same percent. Standard Deviation will increase or decrease by the same percent.
For example:
Standard Deviation of a set: {1,1,4} will be the same as that of {5,5,8} as second set is obtained by adding 4 to each term of the first set.
That's because Standard Deviation shows how much variation there is from the mean. And when adding or subtracting a constant to each term we are shifting the mean of the set by this constant (mean will increase or decrease by the same constant) but the variation from the mean remains the same as all terms are also shifted by the same constant.
So according to this rule, statement (1) is sufficient to get new Standard Deviation, it'll be 30% less than the old.. As for statement (2) it's clearly insufficient as knowing mean gives us no help in getting new Standard Deviation.
There are 10 seniors in the class, from which 4 should be chosen by the teacher. The order of the chosen students does not matter. This means that we speak of combinations. THe equation for calculating the number of possible combinations is:
C=N!/R!(N-R), where N is the total number of objects and R is the number of objects we select from the N
In our case, N=10, R=4.
C= 10!/4!*6!=10*9*8*7*6!/6!*4*3*2*1=<span>10*9*8*7/24=5040/24=210
There are 210 different ways for the teacher to choose 4 seniors in no particular order.</span>
Answer:
its 55
Step-by-step explanation:cuz why not
33-4(3)
33-12
21
The answer is 21
65 total test items were on the test.
