You get a $60,000 loan for a new dump truck. With the truck, you can generate $500 more business each week at 80% margin. Your i
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Answer:
0.04
Step-by-step explanation:
In this case we must use the following formula to be able to find the standard error, which would be the square root, of the probability for its complement divided by the population:
SE=
Now, knowing that p = 0.552 and n = 160 we replace and we are left with:
SE =
SE =
SE = 0.039
Which means that the standard error of the proportion is 0.04
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: