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AlekseyPX
2 years ago
5

A school teacher is worried that the concentration of dangerous, cancer-causing radon gas in her classroom is greater than the s

afe level of 4pCi/L. The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. In order to test whether the average level of radon gas is greater than the safe level, the appropriate hypotheses are:_______
Mathematics
1 answer:
marin [14]2 years ago
7 0

Answer:

H0 ; μ ≤ 4 pCi/L

Ha ; μ > 4 pCi/L

The null hypothesis is that the concentration of dangerous, cancer-causing radon gas in her classroom is less than or equal to the safe level of 4pCi/L

H0 ; μ ≤ 4 pCi/L

The alternative hypothesis is that the concentration of dangerous, cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L.

Ha ; μ > 4 pCi/L

Step-by-step explanation:

The null hypothesis (H0) tries to show that no significant variation exists between variables or that a single variable is no different than its mean. While an alternative Hypothesis (Ha) attempt to prove that a new theory is true rather than the old one. That a variable is significantly different from the mean.

The null hypothesis is that the concentration of dangerous, cancer-causing radon gas in her classroom is less than or equal to the safe level of 4pCi/L

H0 ; μ ≤ 4 pCi/L

The alternative hypothesis is that the concentration of dangerous, cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L.

Ha ; μ > 4 pCi/L

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sandbox 1 area = 5*5 = 25 square m

sandbox 2

25=w*(3w+1)=

3w^2+w-25=0

w=2.7248 (round to 2.72 m)

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6 0
2 years ago
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To avoid collisions with invasive species of aliens, new imperial regulations allow only positive integer space jumps parallel t
Sunny_sXe [5.5K]

Answer:24,942,060

Step-by-step explanation:

(10,10,4) - (3,2,0) = 7,8,4

7+8+4=19

19!/(7!*8!*4!)= 24'942'060

7 0
1 year ago
Show all your work. Indicate clearly the methods you use, because you will be scored on the correctness of your methods as well
laiz [17]

Answer:

The  value is  P(A) =  0.133617

Step-by-step explanation:

From the question we are told that

  The  mean is  \mu =  7.5

  The standard deviation is  \sigma  =  0.2

  The safest water level is  between  7.2 and  7.8

Generally the probability that the selected pool has a pH level that is not considered safe is mathematically represented as

       P(A) =  1 - P(7.2 \le X  \le 7.8 )

Here  

      P(7.2 < X  < 7.8 ) = P(\frac{ 7.2 - \mu }{\sigma } <  \frac{X - \mu }{ \sigma }

Generally \frac{X - \mu }{ \sigma } =  Z (The  \ standardized \  value  \  of  X )

So

 P(7.2 < X  < 7.8 ) = P(\frac{ 7.2 - 7.5 }{0.2 } < Z    

 P(7.2 < X  < 7.8 ) = P(-1.5 < Z  

=>  P(7.2 < X  < 7.8 ) = P(Z <  1.5) - P(  Z < - 1.5)

From the z-table the probability of  (Z <  -1.5) and   (  Z <1.5)  are

    P(Z <  1.5) =  0.93319

and  

    P(Z <  -1.5) =  0.066807

So

      P(7.2 < X  < 7.8 ) =0.93319 - 0.066807

       P(7.2 < X  < 7.8 ) =0.0866383

So

   P(A) =  1 - 0.0866383

=>  P(A) =  0.133617

5 0
2 years ago
Silva set up a dog-walking business. He earned $60 in June. He is projected to earn 110% more in July. How much is Silva project
snow_lady [41]

9514 1404 393

Answer:

  $126

Step-by-step explanation:

110% more than 100% is 210% of his June earnings:

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Silva is projected to make $126 in July.

_____

As always, you can think of % and /100 as being interchangeable.

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7 0
2 years ago
Two percent of the customers of a store buy cigars. Half of the customers who buy cigars buy beer. 25 percent who buy beer buy c
enyata [817]

Answer:

0.95

Step-by-step explanation:

The computation of the probability that a customer neither buys beer nor buys cigars is given below;

Given that, the probabilities are

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And, the customers who purchased beer + cigars be 0.25

Now the probabilities where the customer purchased both

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The probability where the customer purchased beer is

= 0.01 ÷ 0.25

= 0.04

Now the probability where a customer neither buys beer nor buys cigars is

= 1 - 0.02 + 0.04 - 0.01

= 0.95

4 0
2 years ago
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