Caroline bought 20 shares of stock at 10 ½, and after 10 months the value of the stocks was 11 ¼. If Caroline were to sell all h
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Answer:
So on this case the 95% confidence interval would be given by (12.150;16.690)
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
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".
represent the sample mean
population mean (variable of interest)
represent the population standard deviation
n=36 represent the sample size
Solution to the problem
The confidence interval for the mean is given by the following formula:
(1)
Since the Confidence is 0.95 or 95%, the value of and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that
Now we have everything in order to replace into formula (1):
So on this case the 95% confidence interval would be given by (12.150;16.690)
Answer:
5 trees should be planted to maximize the yield per acre,
The maximum yield would be 1250
Step-by-step explanation:
Given,
The original number of trees per acre = 20,
Average pounds of nuts by a tree = 60,
Let x be the times of increment in number of trees,
So, the new number of trees planted per acre = 20 + x
∵ for each additional tree planted per acre, the average yield per tree drops 2 pounds,
So, the new number of pounds of nut = (60 - 2x)
Thus, the total yield per acre,
Differentiating with respect to t ( time ),
Again differentiating with respect to t,
For maxima or minima,
⇒ 20 - 4x = 0
⇒ 20 = 4x
⇒ x = 5,
For x = 5, Y''(x) = negative,
Hence, Y(x) is maximum for x = 5,
And, maximum value of Y(x) = (20+5)(60 - 10) = 25(50) = 1250,
i.e. 5 trees should be planted to maximize the yield per acre,
and the maximum yield would be 1250 pounds