SOLUTION: Hey, I'm having a ton of trouble with these four problems out of a huge packet, could someone please help me out? :] 1. what is the (a)variance, and the (b)standard deviation of

Question 55594This question is from textbook Algebra and Trigonometry
: Hey, I'm having a ton of trouble with these four problems out of a huge packet, could someone please help me out? :]
1. what is the (a)variance, and the (b)standard deviation of the following scores : 51, 55, 61, 62, 68, 71, 71, 73, 81, 82, 87, 89, 92, 94, 95, 100
2. Suppose a contest offers $1,000 to the person who can guess the winning four digit number. How many possibilities are there?
3. Suppose there are 10 items on a true-false quiz. The person taking the test does not read the questions; he just answers the questions randomly. What is the probability of his guessing all answers correctly? This question is from textbook Algebra and Trigonometry

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
1. what is the (a)variance, and the (b)standard deviation of the following scores : 51, 55, 61, 62, 68, 71, 71, 73, 81, 82, 87, 89, 92, 94, 95, 100
a) 216.375 ; b)14.7097
---------------------
2. Suppose a contest offers $1,000 to the person who can guess the winning four digit number. How many possibilities are there?
There are 10^4=10000 4-digit sequences if you allow any of the 10 digits to occupy each of the four digit positions.
What "possibilities" are you looking for?
---------------
3. Suppose there are 10 items on a true-false quiz. The person taking the test does not read the questions; he just answers the questions randomly. What is the probability of his guessing all answers correctly?
Each answer has two possibilities.
The prob of getting one answer correct is 1/2
The probl of getting 10 correct is (1/2)^10 = 1/1024
Cheers,
Stan H.

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