Question 7(Multiple Choice Worth 1 points) (08.02 LC) Eva conducted a survey to find out the amount of time high schoolers spend
1 answer:
Answer:
The answer is "Option B".
Step-by-step explanation:
The difference between most time and also the least spending time on Internet surfing is 3 hours. Since we do not have charts for tables etc., only 3 can be used we need. A range is defined as the difference between the largest and the smallest amounts. The range between both the largest as well as the smallest is unique. In this reply, it tells us that the gap between most time and the fewer hours invested surfing the web is 3 hours.
- In option A, it is wrong since the range has nothing to do with formulas. (Of course, the dividend with a divisor results in a quotient). Only subtraction and not division may be achieved.
- In option C, when all surf for exactly one hour, it could take the largest time of 3 hours and 3 hours, the last time. Add it into the equation and the range of the data present would've been 0.
- In option D, It is erroneous even as the range is not the mean, and the mean seems to be the average. We search for both the range, not the mean.
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Explanation:
Each row in Pascal's triangle is a listing of the values of nCk = n!/(k!(n-k)!) for some fixed n and k in the range 0 to n. nCk is <em>the number of combinations of n things taken k at a time</em>.
If you consider what happens when you multiply out the product (a +b)^n, you can see where the coefficients nCk come from. For example, consider the cube ...
(a +b)^3 = (a +b)(a +b)(a +b)
The highest-degree "a" term will be a^3, the result of multiplying together the first terms of each of the binomials.
The term a^b will have a coefficient that reflects the sum of all the ways you can get a^b by multiplying different combinations of the terms. Here they are ...
- (a +_)(a +_)(_ +b) = a·a·b = a^2b
- (a +_)(_ +b)(a +_) = a·b·a = a^2b
- (_ +b)(a +_)(a +_) = b·a·a = a^2b
Adding these three products together gives 3a^2b, the second term of the expansion.
For this cubic, the third term of the expansion is the sum of the ways you can get ab^2. It is essentially what is shown above, but with "a" and "b" swapped. Hence, there are 3 combinations, and the total is 3ab^2.
Of course, there is only one way to get b^3.
So the expansion of the cube (a+b)^3 is ...
(a +b)^3 = a^3 + 3a^2b +3ab^2 +b^3 . . . . . with coefficients 1, 3, 3, 1 matching the 4th row of Pascal's triangle.
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In short, the values in Pascal's triangle are the values of the number of combinations of n things taken k at a time. The coefficients of a binomial expansion are also the number of combinations of n things taken k at a time. Each term of the expansion of (a+b)^n is of the form (nCk)·a^(n-k)·b^k for k =0 to n.
