Algebra 1 : Statistics and Probability
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Example Questions
Example Question #21 : Statistics And Probability
A student is interested in knowing how much time his classmates spend watching TV each night. He asks them and gets the following results (in minutes).
30, 60, 45, 42, 48, 87, 15, 22, 25, 92, 70, 75
What was the mean time spent watching TV?
30, 60, 45, 42, 48, 87, 15, 22, 25, 92, 70, 75
First, sum the number of minutes spent watching TV by all classmates.
Then, divide the sum by the number of students. There are twelve values, so twelve students answered the question.
Example Question #22 : How To Find Mean
A short quiz with 5 questions is given to a class of 30 students. 7 students answered 5 questions correctly, 12 students answered 4 questions correctly, 9 students answered 3 questions correctly, and 2 students answered 2 questions correctly.
What is the mean number of correct answers among the students in the class?
To find the average score of the class, you must add the total score of all of the students and divide it by the number of students. 7 students answered 5 questions correctly, 12 students answered 4 questions correctly, 9 students answered 3 questions correctly, and 2 students answered 2 questions correctly, so this gives you a total score of 114: 
Example Question #22 : Statistics And Probability
Find the mean of the following set of numbers: 32, 23, 46, 52, 37.
To find the mean, or average, of a set of numbers, you first add all of the numbers together:
Then, you divide the sum by the total number of numbers, which in this set is 5 (i.e., there are 5 numbers in this set):
38 is the mean, or average, of this set of numbers.
Example Question #23 : Statistics And Probability
Find the mean of the following: 65, 70, 91, 85, 89
Example Question #24 : Statistics And Probability
We want to create a three-digit code for a combination lock. Only digits from 0-9 are allowed and digits cannot be repeated. How many such codes can be generated?
The first position can be filled in 10 ways. Since repetition is not allowed, the second position can be filled in 9 ways, and finally the third position can be filled in 8 ways giving us the correct answer of
Example Question #25 : How To Find Mean
We want to create a three-digit code for a combination lock. Only digits from 0-9 are allowed and digits cannot be repeated. Also a code can not start with 0. How many such codes can be generated?
The first position can be filled in 9 ways since 0 is not allowed. In the second position 0 is allowed, less the digit placed in the first position, which gives us 9. Hence the second position can be filled in 9 ways and as before the third position can be filled in only 8 ways which gives us the correct answer of
Example Question #25 : Statistics And Probability
Evaluate:
Hence,
Example Question #26 : Statistics And Probability
Five contestants are competing for the following executive positions, namely,
President, Vice President, and Secretary.
How many ways the executive positions can be filled ?
This is a permutation problem and here the order is important. The correct way to answer this question is to calculate
which equals to
which is 60.
Example Question #27 : Statistics And Probability
If you toss 3 fair coins what is the sample space? (Tossing a coin results in either a Head "H" or a Tail "T")
When you toss a coin, there are two outcomes. Hence when you toss 3 coins the total number of outcomes will be 8 and the sample space is given by:
Example Question #28 : Statistics And Probability
If we toss two dice, what is the probability of rolling doubles?
A double consists of the following set 
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