Write 3.11 as a mix number and a improper fraction?
1 answer:
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Answer: 33 students wore blue jeans .
Step-by-step explanation:
Let x be the number of black pants.
Given : For the choir concert, the choir director has asked that everyone wear either black pants or blue jeans.
Three times as many students wore black pants as blue jeans.
i.e. Number of blue pants = 4x
If there are forty-four students in the choir, then we have
Divide both sides by 4 , we get
Thus , the number of black pants = 11
Then , the number of blue pants =
Therefore, 33 students wore blue jeans .
Answer:
So then the minimum sample to ensure the condition given is n= 38
Step-by-step explanation:
Notation
represent the sample mean for the sample
population mean (variable of interest)
represent the population standard deviation
n represent the sample size
ME = 4 the margin of error desired
Solution to the problem
When we create a confidence interval for the mean the margin of error is given by this formula:
(a)
And on this case we have that ME =4 and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
The critical value for 96% of confidence interval now can be founded using the normal distribution. The significance is . And in excel we can use this formula to find it:"=-NORM.INV(0.02;0;1)", and we got
, replacing into formula (b) we got:
So then the minimum sample to ensure the condition given is n= 38