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.
Answer:
The unit vector in component form is
or
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Step-by-step explanation:
Let be
, its unit vector is determined by following expression:

Where
is the norm of
, which is found by Pythagorean Theorem:


Then, the unit vector is:


The unit vector in component form is
or
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Answer:gnhbk j bmnj
Step-by-step explanation:
Answer:
The principal function of platelets is to prevent bleeding. Red blood cells are the most numerous blood cell, about 5,000,000 per microliter. Red blood cells make up about 40% of our total blood volume, a measure called the hematocrit
Answer:
A,D,E, and F
Step-by-step explanation: