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Anastasy [175]
2 years ago
9

What is f(-1)=-3x^{2}+7x+4

Mathematics
2 answers:
tino4ka555 [31]2 years ago
5 0

Step-by-step explanation:

please mark me as brainlest

Pie2 years ago
5 0
F(-1) = -3(-1)^2 + 7(-1) + 4 = -3 + -7 + 4 = -6
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Rothamsted Experimental Station (England) has studied wheat production since 1852. Each year many small plots of equal size but
podryga [215]

Answer:

(a) 0.653

(b) 0.0198

(c) Yes, after testing we conclude that the population variance of annual wheat production for the first plot is larger than that for the second plot.

Step-by-step explanation:

(a) We are give the sample of one year annual production of wheat (in pounds) ;

4.46, 4.21, 4.40, 4.81, 2.81, 2.90, 4.93, 3.54, 4.16, 4.48, 3.26, 4.74, 4.97, 4.02, 4.91, 2.59

For calculating sample variance, firstly we will calculate mean of the above data;

Mean of above data, X_1bar = Sum of all values ÷ n (no. of values)

                                 = \frac{4.46 + 4.21+4.40+.......+4.91+2.59}{16} = 4.074

Sample Variance, s_1^{2} = \frac{\sum (X-X_1bar)^{2} }{n-1} = \frac{(4.46-4.074)^{2}+(4.21-4.074)^{2}+.........+(4.91-4.074)^{2}+(2.59-4.074)^{2} }{16-1} = 0.653

(b) Another sample for annual wheat production (in pounds);

3.89, 3.81, 3.95, 4.07, 4.01, 3.73, 4.02, 3.78, 3.72, 3.96, 3.62, 3.76, 4.02, 3.73, 3.94, 4.03

Mean of above data, X_2bar = Sum of all values ÷ n (no. of values)

                                 = \frac{3.89+3.81+3.95.......+3.94+4.03}{16} = 3.88

Sample Variance, s_2^{2} = \frac{\sum (X-X_2bar)^{2} }{n-1} = \frac{(3.89-3.88)^{2}+(3.81-3.88)^{2}+.........+(3.94-3.88)^{2}+(4.03-3.88)^{2} }{16-1} = 0.0198

(c) Now, we have to test the claim that population variance of annual wheat production for the first plot is larger than that for the second plot i.e.;

       Null Hypothesis, H_0 : \sigma_1^{2} = \sigma_2^{2}   or H_0 : \frac{\sigma_1^{2} }{\sigma_2^{2} } = 1

Alternate Hypothesis, H_0 : \sigma_1^{2} > \sigma_2^{2}   or H_0 : \frac{\sigma_1^{2} }{\sigma_2^{2} } >  1

The test statistics used here is;

                           \frac{s_1^{2} }{s_2^{2} }* \frac{\sigma_1^{2} }{\sigma_2^{2}}  ~ F_n__1-1_,n_2-1   where, n_1 = 16 and n_2 =16

   Test Statistics = \frac{0.653 }{ 0.0198}* 1 ~ F_1_5_,_1_5

                          = 32.98

Since, we are not provided with any significance level so we assume it to be 5% and at this level, the F table gives critical value of 2.4282.

<em>Since our test statistics is higher than the critical value and it falls in the rejection region so we have sufficient evidence to reject null hypothesis and conclude that the population variance of annual wheat production for the first plot is larger than that for the second plot.</em>

8 0
3 years ago
EMILY COLLECTED $950 SELLING GIRL SCOUT COOKIES ALL DAY SATURDAY. EMILY'S TROOP COLLECTED 10 TIMES AS MUCH AS SHE DID. HOW MUCH
Katyanochek1 [597]
9,500  just add the 0 always add 0 if you multiply by 10. 00 for 100 and 000 for 1000
7 0
3 years ago
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Evaluate 6+3b if b=7
Pavlova-9 [17]
27. Replace b with 7, making 6 + 3(7). The 3 and parentheses of 7 hint multiplication, so you multiply to make 21, then add 6 relating back to PEMDAS to teach you the correct order to solve the problem.
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4 years ago
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Distribute to simplify the expression: 3 ( 2X + 5Y - 4)
IrinaK [193]

Answer:

6X + 15Y - 12

Step-by-step explanation:

3 (2X + 5Y - 4)

Multiply each term by 3

2X * 3 + 5Y * 3 - 4 * 3

6X + 15Y - 12

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4 years ago
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Distribute $1000 into three parts so that one part will be three times as large as the second and the third part will be as larg
Over [174]

Answer:

See below

Step-by-step explanation:

x = part 1

3x = part 2

x + 3x  = part 3       summed, they equal 1000

x    +     3x      +   x + 3x = 1000

8x = 1000

<u>x = 125       3x = 385      third part = 500 </u>

3 0
2 years ago
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