Answer:
Step-by-step explanation:
{x,y}={5,-5}
So the mean is 72.97
We need to subtract the mean from each value and square it.
(65-72.97)^2= 63.5209
(68-72.97)^2=24.7009
(69-72.97)^2=15.7609
(70-72.97)^2=8.8209
(71-72.97)^2= 3.8809
(72-72.97)^2=0.9409
(90-72.97)^2=290.0209
(95-72.97)^2=485.3209
Now we add up the new values ( also consider their frequency) and find their mean.
Add the values
63.5209+(2 •24.7009=49.4018)+(5•15.7609=78.8045)+(8•8.8209=70.5672)+(7•3.8809=27.1663)+(3•0.9409=2.8227)+(2•290.0209=580.0418)+(2•485.3209=970.6418)= 1,842.967
Divide by total numburs to find the mean
1,842.967/ 30=61.43223333
The standar deviation is the square root of the mean so is
Square root of 61.43223333=7.837871735
Round to the nearest tenth
Standard Deviation is 7.8
Answer:
The maximum number of volleyballs that she can buy is 19
Step-by-step explanation:
Let
x ----> the number of volleyballs
we know that
The cost of each volleyball net ($28) by the number of volleyball nets (4) plus the cost of each volleyball ($7) multiplied by the number of volleyballs (x) must be less than or equal to $250
so
The inequality that represent this situation is

Solve for x

subtract 112 both sides


Divide by 7 both sides

therefore
The maximum number of volleyballs that she can buy is 19
Answer:
Approximate probability that the number of households that use the Internet for banking in a sample of 1000 is less than or equal to 130 is less than 0.0005% .
Step-by-step explanation:
We are given that let X be the number that do some or all of their banking on the Internet.
Also; Mean,
= 310/1000 or 0.31 and Standard deviation,
= 14.63/1000 = 0.01463 .
We know that Z =
~ N(0,1)
Probability that the number of households that use the Internet for banking in a sample of 1000 is less than or equal to 130 is given by P(X <= 130/1000);
P(X <=0.13) = P(
<=
) = P(Z <= -12.303) = P(Z > 12.303)
Since this value is not represented in the z table as the value is very high and z table is limited to x = 4.4172.
So, after seeing the table we can say that this probability is approximately less than 0.0005% .
The binomial distribution is given by,
P(X=x) =

q = probability of failure = 1-0.2 = 0.8
n = 100
They have asked to find the probability <span>of obtaining a score less than or equal to 12.
</span>∴ P(X≤12) =

where, x = 0,1,2,3,4,5,6,7,8,9,10,11,12
∴ P(X≤12) =

+

+

+

+

+

+

Evaluating each term and adding them you will get,
P(X≤12) = 0.02532833572
This is the required probability.