If you are given a quadratic equation explain how you would know whether or not the roots are imaginary
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Answer:
The probability is 0.0052
Step-by-step explanation:
Let's call A the event that the four cards are aces, B the event that at least three are aces. So, the probability P(A/B) that all four are aces given that at least three are aces is calculated as:
P(A/B) = P(A∩B)/P(B)
The probability P(B) that at least three are aces is the sum of the following probabilities:
- The four card are aces: This is one hand from the 270,725 differents sets of four cards, so the probability is 1/270,725
- There are exactly 3 aces: we need to calculated how many hands have exactly 3 aces, so we are going to calculate de number of combinations or ways in which we can select k elements from a group of n elements. This can be calculated as:
So, the number of ways to select exactly 3 aces is:
Because we are going to select 3 aces from the 4 in the poker deck and we are going to select 1 card from the 48 that aren't aces. So the probability in this case is 192/270,725
Then, the probability P(B) that at least three are aces is:
On the other hand the probability P(A∩B) that the four cards are aces and at least three are aces is equal to the probability that the four card are aces, so:
P(A∩B) = 1/270,725
Finally, the probability P(A/B) that all four are aces given that at least three are aces is:
Answer:
We conclude that the mean family income for Mexican migrants to the United States is $27,000 per year and the provided information is consistent with the United Nations report.
Step-by-step explanation:
We are given that a United Nations report shows the mean family income for Mexican migrants to the United States is $27,000 per year.
A FLOC evaluation of 25 Mexican family units reveals a mean to be $30,000 with a sample standard deviation of $10,000.
Let = <em><u>true mean family income for Mexican migrants.</u></em>
So, Null Hypothesis, :
= $27,000 {means that the mean family income for Mexican migrants to the United States is $27,000 per year}
Alternate Hypothesis, :
$27,000 {means that the mean family income for Mexican migrants to the United States is different from $27,000 per year}
The test statistics that would be used here <u>One-sample t test statistics</u> as we don't know about the population standard deviation;
T.S. = ~
where, = sample mean family income = $30,000
s = sample standard deviation = $10,000
n = sample of Mexican family = 25
So, <u><em>the test statistics</em></u> = ~
= 1.50
The value of t test statistics is 1.50.
Since, in the question we are not given the level of significance so we assume it to be 5%. <u>Now, at 5% significance level the t table gives critical values of -2.064 and 2.064 at 24 degree of freedom for two-tailed test.</u>
Since our test statistic lies within the range of critical values of t, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which <u>we fail to reject our null hypothesis</u>.
Therefore, we conclude that the mean family income for Mexican migrants to the United States is $27,000 per year and the provided information is consistent with the United Nations report.