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expeople1 [14]
3 years ago
7

The following represents the probability distribution for the daily demand of microcomputers at a local store. Demand Probabilit

y 0 .1 1 .2 2 .3 3 .2 4 .2 The expected daily demand is _____.
Mathematics
1 answer:
konstantin123 [22]3 years ago
8 0

Answer:

The correct answer is 2.2.

Step-by-step explanation:

The following represents the probability distribution for the daily demand of microcomputers at a local store:

Demand Probability

f(0)= .1

f(1)= .2

f(2)= .3

f(3)= .2

f(4)= .2.

Expectation of a discrete probability function f of the random variable x is given by ∑ x × f(x).

Thus the expected value of  demand is given by

0.1 × 0 + 0.2 × 1 + 0.3 × 2 + 0.2 × 3 + 0.2 × 4 = 2.2.

The expected daily demand is 2.2.

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Is there statistically significant evidence that the districts with smaller classes have higher average test​ scores? The t​-sta
Musya8 [376]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The  95% confidence interval is [670.03  , 673.97 ]

The  test statistics is t = 7.7

The  p-value  is    p-value  =  0

The <u>p-value</u>  suggests that the null hypothesis is<u> rejected </u>with a high degree of confidence. Hence  <u>there is</u> statistically significant evidence that the districts with smaller classes have higher average test score  

Step-by-step explanation:

From the question we are told that

   The sample size is  n =  408

    The sample mean is  \= y  =  672.0

   The standard deviation is  s = 20.3

Given that the confidence level  is 95% then the level of significance is  

   \alpha = (100 -95 )\% = 0.05

From the normal distribution table  the critical value of \frac{\alpha }{2} = \frac{0.05 }{2} is  

    Z_{\frac{\alpha }{2} } =  1.96

Generally  the margin of error is mathematically represented as  

     E  =  Z_{\frac{\alpha }{2} } *  \frac{s}{\sqrt{n} }

=>   E  =  1.96 *  \frac{20.3}{\sqrt{408} }

=>     E  =  1.970

Generally the 95% confidence interval is mathematically represented as

       \= y -E  < \mu <  \= y + E

=>     672.0 -1.970  < \mu < 672.0 +1.970

=>     670.03  < \mu < 673.97

=>     [670.03  , 673.97 ]

From the question we are told that

   Class size                                  small                                      large

  Avg.score(\= y)         \= y_1 = 683.7   \= y_2 =  676.0

   S_y                          S_{y_1} =20.2    S_{y_2} = 18.6

   sample size                             n_1 = 229        n_2 =  184

The  null hypothesis is  H_o :  \mu_1 - \mu_2 = 0

The alternative hypothesis is  H_a :  \mu_1 - \mu_2 > 0

Generally the standard error for the difference in mean is mathematically represented as

       SE =  \sqrt{\frac{S_{y_1}^2 }{n_1} +\frac{S_{y_2}^2 }{n_2}   }

=>     SE =  \sqrt{20.2^2 }{229} +\frac{18.6^2 }{184_2}   }

=>     SE =  1.913

Generally the test statistics is mathematically represented as

      t = \frac{\= y _1 - \= y_2 }{SE}

=>    t = \frac{683.7 - 676.0 }{1.913}

=>   t = 7.7

Generally the p-value is mathematically represented as

    p-value  =  P(t >  7.7 )

From the  z-table

        P(t >  7.7 ) =  0

So

   p-value  =  0

From the values we obtained and calculated we can see that p-value  <  \alpha

This mean that

The p-value  suggests that the null hypothesis is rejected with a high degree of confidence. Hence  there is statistically significant evidence that the districts with smaller classes have higher average test score  

4 0
3 years ago
-2 ( 18 - 3y ) = 7y + 2y
katrin [286]

Answer:

y=-12

Step-by-step explanation:

-2(18-3y)=7y+2y

-36+6y=9y

9y-6y=-36

3y=-36

y=-12

4 0
3 years ago
Need help asap please​
cestrela7 [59]

Answer:

9:49 is the answer because question say ratio is square of small and big

6 0
2 years ago
What is the volume help please
Murrr4er [49]

Answer:

Hi there! Your answer would be 136.08, because you must times all 3 numbers they give on the picture.

Step-by-step explanation:

6 0
2 years ago
Read 2 more answers
In a certain Algebra 2 class of 29 students, 13 of them play basketball and 7 of them play baseball. There are 4 students who pl
Inessa [10]

Answer:

16/29

Step-by-step explanation:

P(A∪B) = P(A) + P(B) - P(A∩B)

P(basketball or baseball) = P(basketball) + P(baseball) - P(both)

= (13/29) + (7/29) - (4/29)

= 16/29

The probability that a randomly chosen student plays either sport is 16/29.

3 0
3 years ago
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