N/5 ≥ 11 Please help
2 answers:
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Answer:
a) n =1623
b)
Step-by-step explanation:
1) Notation and definitions
random sample taken
estimated proportion of customers are not satisfied with the service provided by the local dealer
Confidence =0.96 or 96%
Me= 0.02 represent the margin of error
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".
The population proportion have the following distribution
Part a
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 96% of confidence, our significance level would be given by and
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
And replacing into equation (b) the values from part a we got:
And rounded up we have that n=1623
Part b
The margin of error is given by:
So then if w replace the value of n obtained from part a we got:
Answer:
21 students pass
Step-by-step explanation:
Firstly, you can set up the problem into an equation where the variable X would equal the number of students passing. You put X over the total number of students in the class, turning it into a fraction, then set it equal to the fraction (which is 75% represented as a fraction).
The fraction can be simplified, because 75 and 100 are both multiples of 25, so after canceling out the 25s you would be left with
.
Next, you use the process of cross multiplication which is essentially just multiplying the denominators of both fractions (which would be 28 and 4 in this case) to each side of the equation.
The denominators cancel out leaving you with a simple equation to simplify.
Finally, divide both sides by four in order to isolate the variable.
X = 21.