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Rina8888 [55]
3 years ago
11

A bag contains 4 yellow, 2 red, and 6 green marbles. two marbles are drawn. the first is replaced before the second is drawn. a

random variable assigns the number of red marbles to each outcome. calculate the expected value of the random variable.
a. 0.67
c. 0.17
b. 0.56
d. 0.33
Mathematics
2 answers:
lorasvet [3.4K]3 years ago
6 0

Answer:

D. 0.33

Step-by-step explanation:

You multiplied the probability of the marbles by the amount of them and added them up to get your answer. Then convert that answer into a decimal.

Dafna1 [17]3 years ago
5 0

Answer:

c. 0.17

Step-by-step explanation:

The bag have 4 + 2 + 6 = 12 balls.

There are 2 red marbles, in 12, the probability to take one red is 2/12. Is important to remember that the first marble was replaced before the second outcome, so the chance for the second is also 2/12:

2/12 = 1/6 = 0.1666 ≈ 0.17

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Alexus [3.1K]
They both are complementary angles i.e their sum must equals 90°

4x+ 31 + 6x + 39 = 90
10x + 70 = 90
10x = 90-70
10x = 20
x = 2


we have to find angle ADC
just put the value of x in that expression for that angle.

angle ADC = 6x + 39 = 6 (2)+39 = 12 + 39 = 51°

4 0
3 years ago
If tan x=.67, and cos x=.83, what is sin x
Alexxandr [17]

Answer:

0.56

Step-by-step explanation:

                                  sin x

tan x is defined as -------------

                                  cos x

and we can solve this for sin x:  sin x = (cos x)(tan x)

which here is:  sin x = 0.83(0.67) = 0.56 (rounded up from 0.5561)

7 0
3 years ago
Find the area of the figure
sertanlavr [38]

Answer:

75

Step-by-step explanation:

7 0
2 years ago
Read 2 more answers
g A certain financial services company uses surveys of adults age 18 and older to determine if personal financial fitness is cha
leva [86]

Answer:

Null hypothesis:p_{1} = p_{2}    

Alternative hypothesis:p_{1} \neq p_{2}  

z=\frac{0.410-0.35}{\sqrt{0.385(1-0.385)(\frac{1}{1000}+\frac{1}{700})}}=2.502    

p_v =2*P(Z>2.502)= 0.0123    

Comparing the p value with the significance level assumed \alpha=0.05 we see that p_v so we can conclude that we have enough evidence to to reject the null hypothesis, and we can say that the proportion analyzed is significantly different between the two groups at 5% of significance.    

Step-by-step explanation:

Data given and notation    

X_{1}=410 represent the number of people indicating that their financial security was more than fair for the recent year

X_{2}=245 represent the number of people indicating that their financial security was more than fair for the year before

n_{1}=1000 sample 1 selected  

n_{2}=700 sample 2 selected  

p_{1}=\frac{410}{1000}=0.410 represent the proportion estimated of indicating that their financial security was more than fair this year

p_{2}=\frac{245}{700}=0.35 represent the proportion estimated of indicating that their financial security was more than fair the year before

\hat p represent the pooled estimate of p

z would represent the statistic (variable of interest)    

p_v represent the value for the test (variable of interest)  

\alpha significance level given  

Concepts and formulas to use    

We need to conduct a hypothesis in order to check if is there is a difference between the two proportions, the system of hypothesis would be:    

Null hypothesis:p_{1} = p_{2}    

Alternative hypothesis:p_{1} \neq p_{2}    

We need to apply a z test to compare proportions, and the statistic is given by:    

z=\frac{p_{1}-p_{2}}{\sqrt{\hat p (1-\hat p)(\frac{1}{n_{1}}+\frac{1}{n_{2}})}}   (1)  

Where \hat p=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}=\frac{410+245}{1000+700}=0.385  

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.    

Calculate the statistic  

Replacing in formula (1) the values obtained we got this:    

z=\frac{0.410-0.35}{\sqrt{0.385(1-0.385)(\frac{1}{1000}+\frac{1}{700})}}=2.502    

Statistical decision  

Since is a two sided test the p value would be:    

p_v =2*P(Z>2.502)= 0.0123    

Comparing the p value with the significance level assumed \alpha=0.05 we see that p_v so we can conclude that we have enough evidence to to reject the null hypothesis, and we can say that the proportion analyzed is significantly different between the two groups at 5% of significance.    

7 0
3 years ago
13/15 is equal to or less than or greater than 0.5
Bess [88]

Answer:

Greater Than

Step-by-step explanation:

Half of 15 is 7 1/2 and 13 is greater than 7 1/2

5 0
1 year ago
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