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 Probability-and-statistics/634807: In a board of directors composed of nine people, how many ways can a chief executive officer, a director, and a treasurer be selected?1 solutions Answer 399913 by ewatrrr(10682)   on 2012-08-05 08:50:21 (Show Source): You can put this solution on YOUR website! ``` Hi In a board of directors composed of nine people, how many ways can a chief executive officer, a director, and a treasurer be selected? Order Important: 9P3 = 9!/6! = ways ```
 Probability-and-statistics/634822: In order to survey the opinions of costumers at shopping malls a researcher decides to select 5 malls from a total of 9 malls in a specific geographic area. How many different ways can the selection be made?1 solutions Answer 399912 by ewatrrr(10682)   on 2012-08-05 08:46:28 (Show Source): You can put this solution on YOUR website! ``` Hi select 5 malls from a total of 9 malls 9C5 = = = 126 }}} ```
 Probability-and-statistics/634829: IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. Find the x-score that corresponds to a z-score of -1.6451 solutions Answer 399911 by ewatrrr(10682)   on 2012-08-05 08:37:41 (Show Source): You can put this solution on YOUR website! ``` Hi or 75 ```
 Probability-and-statistics/634831: Find the area under the standard normal curve between z = 0 and z = 31 solutions Answer 399909 by ewatrrr(10682)   on 2012-08-05 08:28:51 (Show Source): You can put this solution on YOUR website! ``` Hi, Find the area under the standard normal curve between z = 0 and z = 3 % For the normal distribution: one standard deviation from the mean accounts for about 68.2% of the set two standard deviations from the mean account for about 95.4% and three standard deviations from the mean account for about 99.7%. Important to Understand z -values as they relate to the Standard Normal curve: Below: z = 0, z = ± 1, z= ±2 , z= ±3 are plotted. Note: z = 0 (x value the mean) 50% of the area under the curve is to the left and 50% to the right ```
 Probability-and-statistics/634832: Find the z-scores for which 90% of the distribution's area lies between -z and z.1 solutions Answer 399908 by ewatrrr(10682)   on 2012-08-05 08:21:45 (Show Source): You can put this solution on YOUR website! ``` Hi, Find the z-scores for which 90% of the distribution's area lies between -z and z. z = ± 1.751 a a/2 2-tailed crtical regions 80% 0.2 10% z <-1.28155 z >+1.28155 90% 0.1 5% z <-1.645 z >+1.645 92% 0.08 4% z <-1.751 z >+1.751 95% 0.05 2.50% z <-1.96 z >+1.96 98% 0.02 1% z <-2.326 z >+2.326 99% 0.01 0.50% z<-2.576 z >+2.576 Important to Understand z -values as they relate to the Standard Normal curve: Below: z = 0, z = ± 1, z= ±2 , z= ±3 are plotted. Note: z = 0 (x value the mean) 50% of the area under the curve is to the left and 50% to the right ```
 Probability-and-statistics/634827: r the standard normal curve, find the z-score that corresponds to the 90th percentile?1 solutions Answer 399907 by ewatrrr(10682)   on 2012-08-05 08:18:07 (Show Source): You can put this solution on YOUR website! ``` Hi, r the standard normal curve, find the z-score that corresponds to the 90th percentile? Excel function NORMSINV(.90) = 1.2816 Important to Understand z -values as they relate to the Standard Normal curve: Below: z = 0, z = ± 1, z= ±2 , z= ±3 are plotted. Note: z = 0 (x value the mean) 50% of the area under the curve is to the left and 50% to the right ```
 Probability-and-statistics/634809: How many different signals using three distinct flags can be made if there are five different flags from which to select?1 solutions Answer 399906 by ewatrrr(10682)   on 2012-08-05 08:11:55 (Show Source): You can put this solution on YOUR website! ``` Hi, How many different signals using three distinct flags can be made if there are five different flags from which to select? Order Important: 5P3 = 5!/2! = ```
 Probability-and-statistics/634817: In how many ways can 12 different cars be displayed along the circumference of a parking area?1 solutions Answer 399905 by ewatrrr(10682)   on 2012-08-05 08:04:24 (Show Source): You can put this solution on YOUR website! ``` Hi, In how many ways can different cars be displayed along the circumference of a parking area? As in a 'circle' (12-1)! = 11! ```
 Probability-and-statistics/634821: An inspector must select three tests to perform in a certain order on a manufactured part.He has a choice of seven tests. How many ways can he perform three different tests?1 solutions Answer 399903 by ewatrrr(10682)   on 2012-08-05 08:02:48 (Show Source): You can put this solution on YOUR website! ``` Hi, An inspector must select three tests to perform in a certain order on a manufactured part. He has a choice of seven tests. How many ways can he perform three different tests? 7P3 = 7!/4! = ```
 Probability-and-statistics/634819: How many different codes can be made using letters of the word BEAUTY if each code must contain 3 letters?1 solutions Answer 399901 by ewatrrr(10682)   on 2012-08-05 08:00:07 (Show Source): You can put this solution on YOUR website! ``` Hi, How many different codes can be made using the letters of the word BEAUTY if each code must contain 3 letters? ways if no letter is to be repeated ways if repetition is allowed ```
 Probability-and-statistics/634815: How many different 4-digit numbers can be formed from the digits 2, 3,4,5,6,7, and 8 if: a. Repetition of digits is not allowed? b. Repetition of digits is allowed? c.How many of them are odd numbers? Refer to letter a. d. How many of them are even numbers? Refer to letter b.1 solutions Answer 399900 by ewatrrr(10682)   on 2012-08-05 07:57:07 (Show Source): You can put this solution on YOUR website! ``` Hi, How many different 4-digit numbers can be formed from the digits 2, 3,4,5,6,7, and 8 if: a. Repetition of digits is not allowed? b. Repetition of digits is allowed? c.How many of them are odd numbers? Refer to letter a. d. How many of them are even numbers?Refer to letter b. ```
 Probability-and-statistics/634810: How many different ways can a visiting nurse see seven patients if she sees them all in one day/1 solutions Answer 399899 by ewatrrr(10682)   on 2012-08-05 07:44:11 (Show Source): You can put this solution on YOUR website! ``` Hi, How many different ways can a visiting nurse see seven patients if she sees them all in one day. 7! ways ```
 Permutations/634811: Find the number of ways in which nine books can be arranged in a shelf if four particular books are to be kept together.1 solutions Answer 399898 by ewatrrr(10682)   on 2012-08-05 07:41:38 (Show Source): You can put this solution on YOUR website! ``` Hi, ways in which nine books can be arranged in a shelf if four particular books are to be kept together. 4 books as one Unit or 24 ways they can sit together on the shelf ALL nine: = 17,280 ways ```
 Distributive-associative-commutative-properties/634683: Factor. 8x^4-501 solutions Answer 399817 by ewatrrr(10682)   on 2012-08-04 16:55:53 (Show Source): You can put this solution on YOUR website! ``` Hi, 8x^4-50= 2(4x^2 - 25) = 2(2x-5)(2x+5) ```
 Linear-equations/634684: Solve D=ABC solve for B1 solutions Answer 399816 by ewatrrr(10682)   on 2012-08-04 16:53:26 (Show Source): You can put this solution on YOUR website! ``` Hi, D=ABC ⇒ B= D/AC ```
 Exponents/634606: Solve the following exponential equations: a) 7^x=49 b) 243 = 9^2x+1 c) 2^2x * 4^4x +8 = 64 d)9^x-1 * 81 ^2x-1 = 27^3x-21 solutions Answer 399815 by ewatrrr(10682)   on 2012-08-04 16:50:49 (Show Source): You can put this solution on YOUR website! ``` Hi, the idea is to have the base numbers the same ⇒ Exponents are Equal a) 7^x=49 ⇒ 7^x = 7^2 ⇒ x = 2 b) 243 = 9^2x+1 ⇒ ⇒ 5 = 2(2x+1), x = 3/4 c) 2^2x * 4^4x +8 = 64 ⇒ , x= -1 d)9^x-1 * 81 ^2x-1 = 27^3x-2 ⇒ x = 0 ```
 Graphs/634641: Use a number line to graph the solution set to the inequality. xis greater than or equal to -21 solutions Answer 399814 by ewatrrr(10682)   on 2012-08-04 16:35:35 (Show Source): You can put this solution on YOUR website! ``` Hi, x ≥ -2 Draw an arrow to the right with a closed circle on the -2 ```
 Probability-and-statistics/634632: Find the z-scores for which 90% of the distribution's area lies between -z and z.1 solutions Answer 399813 by ewatrrr(10682)   on 2012-08-04 16:30:43 (Show Source): You can put this solution on YOUR website! ``` Hi, Find the z-scores for which 90% of the distribution's area lies between -z and z. -1.6449 < z < 1.6449 Excel function: NORMSINV(.05) = 1.64485 For the normal distribution: one standard deviation from the mean accounts for about 68.2% of the set two standard deviations from the mean account for about 95.4% and three standard deviations from the mean account for about 99.7%. Important to Understand z -values as they relate to the Standard Normal curve: Below: z = 0, z = ± 1, z= ±2 , z= ±3 are plotted. Note: z = 0 (x value the mean) 50% of the area under the curve is to the left and 50% to the right a a/2 2-tailed crtical regions 80% 0.2 10% z <-1.28155 z >+1.28155 90% 0.1 5% z <-1.645 z >+1.645 92% 0.08 4% z <-1.751 z >+1.751 95% 0.05 2.50% z <-1.96 z >+1.96 98% 0.02 1% z <-2.326 z >+2.326 99% 0.01 0.50% z<-2.576 z >+2.576 ```
 Probability-and-statistics/634635: From a group of 6 men and 8 women, 5 people are chosen at random. Find the probability that there are more men chosen than women?1 solutions Answer 399812 by ewatrrr(10682)   on 2012-08-04 16:22:58 (Show Source): You can put this solution on YOUR website! ``` Hi, Previously Posted From a group of 6 men and 8 women, 5 people are chosen at random. P(more men than women) = P(3M&2W) + P(4M&1W) = = ```
 Probability-and-statistics/634636: From a group of 6 men and 8 women, 5 people are chosen at random. Find the probability that there are more men chosen than women?1 solutions Answer 399811 by ewatrrr(10682)   on 2012-08-04 16:21:48 (Show Source): You can put this solution on YOUR website! ``` Hi, From a group of 6 men and 8 women, 5 people are chosen at random. P9more men than women) = P(3M&2W) + P(4M&1W) = = ```
 Sequences-and-series/634668: Sequence: 3, -6, 12, -24, 48,..., find S(sub 20). If S(sub 0)= 3. Then find the sum through S(sub 20). Thank you so much for your time, and everything in helping me understand this problem! Thank you!1 solutions Answer 399810 by ewatrrr(10682)   on 2012-08-04 16:09:04 (Show Source): You can put this solution on YOUR website! ``` Hi, 3, -6, 12, -24, 48,..., Geometric Series, r = -2 ```
 Trigonometry-basics/634679: Solve the following system of equations and check. Either an algebraic or graphic method will be accepted. x²+y²=25 3x-4y=01 solutions Answer 399807 by ewatrrr(10682)   on 2012-08-04 15:51:53 (Show Source): You can put this solution on YOUR website! ``` Hi, 3x-4y=0 OR = y = (3/4)x x^2 = 16 x = ± 4 and y = ± 3 (4,3) and (-4,-3) the solutions to this system of EQs ```
 Expressions-with-variables/634643: solve the following system of equations X – 3z = -5 2x- y + 2z= 16 7x – 3y -5z =19 can you walk me thru the steps please1 solutions Answer 399800 by ewatrrr(10682)   on 2012-08-04 15:40:57 (Show Source): You can put this solution on YOUR website! ``` Hi, x- 3z = -5 | x = 3z- 5 Have a relationship between x and z, so...eliminating y from the other two EQs 2x- y + 2z= 16 |mulitplying 1st by 3 and subtracting it form the 2nd EQ 7x – 3y -5z =19 x - 11z = -29 (3z- 5 - 11z = -29 -8z = -24 z = 3 and x = 4 and y = ```
 Graphs/634656: I think this is a graphing question: Find the coordinates of the vertex for the parabola f(x)=-2x^2-2x.1 solutions Answer 399770 by ewatrrr(10682)   on 2012-08-04 14:00:56 (Show Source): You can put this solution on YOUR website! ``` Hi, Find the coordinates of the vertex for the parabola f(x)= -2x^2-2x. | completing the Square to find the Vertex: y = ax^2 + bx + c ⇒ y = a(x -(-b/2a)^2) - a(-b/2a)^2 + c f(x) = -2(x+1/2)^2 + 1/2 V(-1/2,1/2) the vertex form of a Parabola opening up(a>0) or down(a<0)is: where(h,k) is the vertex ```
 Sequences-and-series/634655: In sequence 3, 7, 11, 15, 19..., find S(sub 50). If S(sub 0)= 3 Thank you so much in helping me!1 solutions Answer 399769 by ewatrrr(10682)   on 2012-08-04 13:49:25 (Show Source): You can put this solution on YOUR website! ``` Hi, Re TY, one may use either of the 2 formulas*** to find the sum 3, 7, 11, 15, 19..., Arithmetic sequence, d = 4 For sums of an arithmetic sequence one can use: *** OR *** |Using the Latter after finding ⇒ ```
 Sequences-and-series/634654: In the arithmetic sequence: a(sub 5) =0, and a(sub 25) =8. What is a(sub 2)? Thank you very much for helping me out! For you time and everything! Thank you very much!1 solutions Answer 399768 by ewatrrr(10682)   on 2012-08-04 13:45:22 (Show Source): You can put this solution on YOUR website! ``` Hi, ⇒ ⇒ d = 8/20 = 2/5 { -8/5, -6/5, -4/5, -2/5, 0, ... } ```
 test/634579: Let f (x, y) = x2 + 2xy + 2y2 − 6y + 2. Find & identify all relative max’s and min’s.1 solutions Answer 399766 by ewatrrr(10682)   on 2012-08-04 13:32:03 (Show Source): You can put this solution on YOUR website! ``` Hi, Previously Posted f(x, y) = x^2 + 2xy + 2y^2 -6y + 2 ∂ f/∂ x = 2x + 2y ∂ f/∂ y = 4y + 2x - 6 2x + 2y = 0 2x + 4y = 6 2y = 6 y = 3 and x = -3 = 2 = 2 = 4 D = f(x,y) has minimum at (-3,3) f(-3, 3) = 9 -18 +18 -18 + 2 = - 7 ```
 test/634516: Let f (x, y) = x2 + 2xy + 2y2 − 6y + 2. Find and identify all relative max’s and min’s.1 solutions Answer 399762 by ewatrrr(10682)   on 2012-08-04 13:22:05 (Show Source): You can put this solution on YOUR website! ``` Hi, f(x, y) = x^2 + 2xy + 2y^2 -6y + 2 ∂ f/∂ x = 2x + 2y ∂ f/∂ y = 4y + 2x - 6 2x + 2y = 0 2x + 4y = 6 2y = 6 y = 3 and x = -3 = 2 = 2 = 4 D = f(x,y) has minimum at (-3,3) f(-3, 3) = 9 -18 +18 -18 + 2 = -7 ```
 test/634578: Let z = f (x, y) = e2x-3y , find: a) fx (1,2) b) fy (-2,3) c) fxx d) fxy e) fyy1 solutions Answer 399758 by ewatrrr(10682)   on 2012-08-04 12:31:47 (Show Source): You can put this solution on YOUR website! ``` Hi, z = f (x, y) = e2x−3y z needs to be clarified using parenthesis ∂f/∂x (1,2) ∂f/∂y (-2,3) Second-order partial Derivatives ```
 Square-cubic-other-roots/634615: sqrt98p^4q^121 solutions Answer 399743 by ewatrrr(10682)   on 2012-08-04 11:43:57 (Show Source): You can put this solution on YOUR website!``` Hi, the idea is to find a perfect square in 98... ```
 Quadratic_Equations/634618: I know that the solutions of this problem are imaginary, but I don't think I solved it right. The problem is x^2+7x+14 and I believe the imaginary solutions are -7+iradical-7/2 and -7-iradical-7/2. Are these right?1 solutions Answer 399741 by ewatrrr(10682)   on 2012-08-04 11:29:25 (Show Source): You can put this solution on YOUR website!``` Hi, Re TY, as to as i^2 = -1 x^2+7x+14 = 0 |Note 2 is the denominator for both terms ```