121 is big enough to assume normality and not worry about the t distribution. By the 68-95-99.7 rule a 95% confidence interval includes plus or minus two standard deviations. So 95% of the cars will be in the mph range

The question is a bit vague, but it seems we're being asked for the 95% confidence interval on the average of 121 cars. The 121 is a hint of course.
The standard deviation of the average is in general the standard deviation of the individual samples divided by the square root of n:

So repeating our experiment of taking the average 121 cars over and over, we expect 95% of the averages to be in the mph range

That's probably the answer they're looking for.
 
        
             
        
        
        
creo que paco es el mayor. lo siento si me equivoco! no soy muy buena en las proporciones
 
        
             
        
        
        
Answer:
755 gram lighter
Step-by-step explanation:
Convert 1.1kg into gram by multiplying it with 1000
1.1 x 1000= 1100 and we take this amount and subtract it with 345g
1100-345= 755g
 
        
             
        
        
        
425 inches, Multiply all the numbers and you get the answer.
        
             
        
        
        
9514 1404 393
Answer:
    A, D
Step-by-step explanation:
The horizontal distance between the points is the difference of their x-coordinates. 
A) 5.5 -(-6.5) = 12.0 . . . greater than 11
B) 4.7 -(-3.3) = 8.0
C) 11/3 -(-10/3) = 21/3 = 7
D) 2 -(-12) = 14 . . . greater than 11