Answer:
0.8417
Step-by-step explanation:
The probability that a college student uses Twitter for social networking is
then the probability that a college student does not use Twitter for social networking is 
9 students are chosen at random.
Use the binomial probability formula to find the probability that 8 use Twitter:
Use the binomial probability formula to find the probability that 9 use Twitter:

The probability that more than 7 students use Twitter is
Answer:
B and F
Step-by-step explanation:
The fourth quadrant contains a positive number for the x axis and a negative number for the y axis. (B=4,-5 and F=4,-7)
She will need 12 hours to read the rest of the book.
They would have used a total of 30 horses. Each person would've each ridden 15 so 15+15= 30 and 165 divided by 11 is 15. Hope this is off help!
Answer:
The range is: 13. The population mean is: 8.5. The population variance is: 15.85. The population standard deviation is: 3.9812.
Step-by-step explanation:
The range: 15 - 2 = 13
The population mean is:
Mean = ( 2 + 9 + 15 + 5 + 14 + 8 + 11 + 7 + 4 + 10 ) / 10 = 8.5
The population variance ( S² or Sigma² ):
S ² = 1/10 · ( ( 2 - 8.5 )² + ( 9 - 8.5 )² + ( 15 - 8.5 )² + ( 5 - 8.5 )² + ( 14 - 8.5 )² + ( 8 - 8.5 )² + ( 11 - 8.5 )² + ( 7 - 8.5 )² + ( 4 - 8.5 )² + ( 10 - 8.5 )² )
S ² = 15.85
The population standard deviation:
S = √(S²) = √15.85 = 3.9812