Answer:
And using a calculator, excel ir the normal standard table we have that:
And we can calculate the probability like this:
Step-by-step explanation:
A random sample of 36 observations has been drawn from a normal distribution with mean 50 and standard deviation 12. Find the probability that the sample mean is in the interval 47<=X<53. Is the assumption of normality important. Why?
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where 
and 
Since the distribution for X is normal then we know that the distribution for the sample mean 
is given by:
We can find the probability required like this:
And using a calculator, excel ir the normal standard table we have that:
And we can calculate the probability like this:
Where is it? I can’t help you without it.
(10 raised to the power of 6)×3
(10*6) ×3
Answer: ₱40,909.1
Step-by-step explanation:
Given data:
Rate for first year = 4%
Rate for next two years = 6%
Rate for the next 3 years = 7.5%
Interest paid back after 5years = ₱ 15,750
Solution:
How much did she borrow.
= let the sum borrowed be P
= P * 4 / 100
= 4P/100
= 1P/25.
For the next two years
= P* 6 * 2/100
= 12P/100
= 3P/25
For the next 3years
= P* 7.5*3/100
= 22.5P/100
= 9P/40.
1P/25 + 3P/25 + 9P/40 = 15750
77P/200 = 15750
P = 15750 * 200 / 77
P = 315,0000/77
P = ₱40,909.1
The amount borrowed is ₱40,909.1
Answer:
- Andre subtracted 3x from both sides
- Diego subtracted 2x from both sides
Step-by-step explanation:
<u>Andre</u>
Comparing the result of Andre's work with the original, we see that the "3x" term on the right is missing, and the x-term on the left is 3x less than it was. It is clear that Andre subtracted 3x from both sides of the equation.
__
<u>Diego</u>
Comparing the result of Diego's work with the original, we see that the "2x" term on the left is missing, and the x-term on the right is 2x less than it was. It is clear that Diego subtracted 2x from both sides of the equation.
_____
<em>Comment on their work</em>
IMO, Diego has the right idea, as his result leaves the x-term with a positive coefficient. He can add 8 and he's finished, having found that x=14.
Andre can subtract 6 to isolate the variable term, and that will give him -x=-14. This requires another step to get to x=14. Sometimes minus signs get lost, so this would not be my preferred sequence of steps.
As a rule, I like to add the opposite of the variable term with the least (most negative) coefficient. This results in the variable having a positive coefficient, making errors easier to avoid.
