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
300 messages would have to be sent or received in order for the plan to cost same each month.
Step-by-step explanation:
Given,
Cost per month = $30
Per text sent or received charges = $0.10
Let,
x be the number of texts sent or received.
A(x) = 0.10x+30
A comparable plan costs = $60 per month
Text messages are unlimited.
B(x) = 60
For the two plans to cost equal;
A(x) = B(x)
Dividing both sides by 0.10
300 messages would have to be sent or received in order for the plan to cost same each month.
Keywords: function, addition
Learn more about functions at:
#LearnwithBrainly
Answer:
1.) mean
2.) H0 : μ = 64
3.) 0.0028
4) Yes
Step-by-step explanation:
Null hypothesis ; H0 : μ = 64
Alternative hypothesis ; H1 : μ < 64
From the data Given :
70; 45; 55; 60; 65; 55; 55; 60; 50; 55
Using calculator :
Xbar = 57
Sample size, n = 10
Standard deviation, s = 7.14
Test statistic :
(xbar - μ) ÷ s/sqrt(n)
(57 - 64) ÷ 8 / sqrt(10)
Test statistic = - 2.77
Pvalue = (Z < - 2.77) = 0.0028 ( Z probability calculator)
α = 10% = 0.1
Reject H0 ; if P < α
Here,
P < α ; Hence, we reject the null
Answer:
D.
Step-by-step explanation:
None of the above because I believe that it is <em>points</em>
X=9
Y=2 i think it’s the answer
