How do I find the equivalent

A random sample of 121 automobiles traveling on an interstate showed an average speed of 73 mph. from past information, it is kn

tatiyna

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

$(73 - 2 \cdot 11, 73 + 2 \cdot 11) = (51,95)$

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:

$\sigma = \dfrac{ 11}{\sqrt{121}} = 1$

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

$(73 - 2 \cdot 1, 73 + 2 \cdot 1) = (71,75)$

That's probably the answer they're looking for.

4 0

3 years ago

Can someone solve these equations with the work, and explain how to do them? I'm completely lost and it's due tomorrow, plus ano

trapecia [35]

Yea what's the equations??

4 0

2 years ago

Farmer Brown has 42 animals, which are cows and chickens. They have a total of 120 legs. Write a system of equations, show your

SCORPION-xisa [38]

Answer:

The system of equations is:

x + y = 42

4x + 2y = 120

And there are 24 chickens.

Step-by-step explanation:

We know that the total number of cows (x) plus the total number of chickens (y) is 42, because Farmer Brown has 42 animals.

We also know that cows (x) have 4 legs and so 4 times the number of cows is the number of cow legs. And chickens (y) have 2 legs, so the number of chickens times two represents the total chicken legs. The sum of 4x + 2y is 120 because there are 120 legs in total.

To solve the system of equations, first solve each equation for y.

In the first equation:

x + y = 42

Subtract x from both sides to isolate y.

y = 42 - x

Second equation:

4x + 2y = 120

Subtract 4x from both sides

2y = 120 - 4x

Divide both sides by 2

y = 60 - 2x

Now that the y's are isolated in both equation, you can put them into 1 equation. Where y = y:

y = 42 - x

y = 60 - 2x

42 - x = 60 - 2x

Add 2x to both sides

42 + x = 60

Subtract 42 from both sides

x = 18

Since x is the number of cows, we know that Farmer Brown has 18 cows.

Now we can substitute the x value into one of the equations:

y = 42 - x

y = 42 - (18)

y = 24

The number of chickens is represented by y, so there are 24 chickens.

3 0

2 years ago

If a set xy-axes has 20 grid units in each direction and the greatest value of the data to be placed on the horizontal axis is 1

Alborosie

Use 7 scale point.
132/20 = 6.6
to its better to use more than 6.6 scale. to make it easier use 7, so to avoid decimals

4 0

2 years ago

Write in decimal form<br> 7+3/100+9/1000 =

SpyIntel [72]

Answer:

7.039

Step-by-step explanation:

8 0

2 years ago