That is a very good question....
Look Grank
you know that:
confidence interval = mean +or- Margin of Error
and
Margin of Error = (z)*(standard deviation) / (sqrt of n)
where n is the number of sample records
So we need to calculate z-value firstly
It says: "<span>we want 90% confidence"
So that:
</span>
<span>confidence90% corresponds to z-value of 1.645
Plug that into our formula of </span><span>Margin of Error:
</span>Margin of Error = (1.645)*(22) / (sqrt of n)
"The sample mean is within 2.7 lb of the population mean" means that Margin of Error is 2.7
<span>Margin of Error:
</span>2.7 = (1.645)*(22) / (sqrt of n)
Now solve for n:
n=179.66~180
SO that 180<span> women must be randomly selected to estimate the mean weight of women in one age group.</span>
Px - 45 = QX + 75
Px - Qx = 75 + 45 = 120
A. If P = - 45 and Q = - 75, then
- 45x + 75 x = 120
30x = 120 and x = 40
B. If P = 45 and Q = - 15, then
45x - 15x = 120
30x = 120
x = 40
D. If P = 15 and Q = 75, then
15x - 75x = 120
- 60x = 120
x = - 2
C. If P = 15 and Q = 15, then
15x - 15x = 120
0 = 120 which is absurd.
Hence, P = 15 and Q = 15 result in an equation with no solution.
Answer:
$240
Step-by-step explanation:
I = prt
I = (2,400) (0.04) (2.5)
note: I changed 4% to a decimal and 30 months to 2.5 years
I = 96 (2.5)
I = 240 <-- The interest
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The simple interest accumulated on a principal of $ 2,400.00 at a rate of 4% per year for 2.5 years (30 months) is $240.00.
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* Last time I did interest was in 6th grade and I don't remember much. So I am very sorry if my answer is wrong *
(17-7)*2=weekly allowance
so her weekly allowance is 20