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Tems11 [23]
3 years ago
7

A psychological researcher did a study with a sample of 84 boys and found that the meam length of time that they remained engage

d with a science exhibit at a museum was 107 second. assuming that from past studies it was known that the population standard deviation was 11.7
a) the best estimate for the population mean u is__

b) find the 99% confidence interval of mean length of time for a recent population

Please helppppppp

Mathematics
1 answer:
Varvara68 [4.7K]3 years ago
4 0
Sample size= n= 84
sample mean= x = 107 s
population standard deviation =σ= 11.7

As, population standard deviation is given so we use the estimate:
                             x(+/-) z(α/2)(σ/√n)

At 99% Confidence interval means significance level is α=1-0.99= 0.01
So,
α/2=0.005
Now, z at α/2=0.005 
z= 2.576
Now, by putting values 
                               107(+/-)((2.576)(11.7/√84)) 
              ( 107-((2.576)(11.7/√84)), 107+((2.576)(11.7/√84))  )    
               (103.7, 110.288)                      


                                         
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LekaFEV [45]
<span>We have 75 mL of 4% sugar solution.
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I can't get the equation to solve.
Did you type it correctly? For one thing, you have the percentages typed as .30 % and 4%.  Are the decimal places in the correct positions?

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3 years ago
PLEASE HELP ME .......!!
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Answer:

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Step-by-step explanation:

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3 years ago
mrs. diaz has 9 eggs. she cooks 5 eggs for breakfast. how many eggs are left? which model shows the problem?
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Answer:

B

Step-by-step explanation:

Because 9 = 5 +4

7 0
2 years ago
Find x, y, and z such that x³+y³+z³=k, for each k from 1 to 100.​
love history [14]

Answer:

x3+y3+z3=k  with k is integer from 1 to 100

solution x=0 , y=0 and z=1 and k= 1

For K= 1 , we have the following solutions (x,y,x) = (1,0,0) ; or (0,1,0) ; or (0,0,1) ,

For k =1 also (9,-8,-6) or (9,-6,-8) or (-8,-6,9) or (-8,9,-6) or (-6,-8,9) or (-6,9,8)

And (-1,1,1) or (1,-1,1)

=>(x+y)3−3x2−3xy2+z3=k

=>(x+y+z)3−3(x+y)2.z−3(x+y).z2=k

=>(x+y+z)3−3(x+y)z[(x+y)−3z]=k

lety=αand z=β

=>x3=−α3−β3+k

For k= 2 we have (x,y,z) = (1,1,0) or (1,0,1) or (0,1,1)

Also for (x,y,z) = (7,-6,-5) or (7,-6,-5) or (-6,-5,7) or (-6,7,-5) or (-5,-6,7) or (-5,7,-6)

For k= 3 we have 1 solution : (x,y,z) = (1,1,1)

For k= 10 , we have the solutions (x,y,z) = (1,1,2) or (1,2,1) or (2,1,1)

For k= 9 we have the solutions (x,y,z) = (1,0,2) or (1,2,0) or (0,1,2) or (0,2,1) or (2,0,1) or (2,1,0)

For k= 8 we have (x,y,z) = ( 0,0,2) or (2,0,0) or (0,2,0)

For k= 17 => (x,y,z) = (1,2,2) or (2,1,2) or ( 2,2,1)

For k = 24 we have (x,y,z) = (2,2,2)

For k= 27 => (x,y,z) = (0,0,3) or (3,0,0) or (0,3,0)

for k= 28 => (x,y,z) = (1,0,3) or (1,3,0) or (1,3,0) or (1,0,3) or (3,0,1) or (3,1,0)

For k=29 => (x,y,z) = (1,1,3) or (1,3,1) or (3,1,1)

For k = 35 we have (x,y,z) = (0,2,3) or (0,3,2) or (3,0,2) or (3,2,0) or 2,0,3) or (2,3,0)

For k =36

we have also solution : x=1,y=2andz=3=>

13+23+33=1+8+27=36 with k= 36 , we have the following

we Have : (x, y,z) = (1, 2, 3) ; (3,2,1); (1,3,2) ; (2,1,3) ; (2,3,1), and (3,1,2)

For k= 43 we have (x,y,z) = (2,2,3) or (2,3,2) or (3,2,2)

For k = 44 we have ( 8,-7,-5) or (8,-5,-7) or (-5,-7,8) or ( -5,8,-7) or (-7,-5,8) or (-7,8,-5)

For k =54 => (x,y,z) = (13,-11,-7) ,

for k = 55 => (x,y,z) = (1,3,3) or (3,1,3) or (3,1,1)

and (x,y,z) = (10,-9,-6) or (10,-6,-9) or ( -6,10,-9) or (-6,-9,10) or (-9,10,-6) or (-9,-6,10)

For k = 62 => (x,y,z) = (3,3,2) or (2,3,3) or (3,2,3)

For k =64 => (x,y,z) = (0,0,4) or (0,4,0) or (4,0,0)

For k= 65 => (x,y,z) = (1,0,4) or (1,4,0) or (0,1,4) or (0,4,1) or (4,1,0) or (4,0,1)

For k= 66 => (x,y,z) = (1,1,4) or (1,4,1) or (4,1,1)

For k = 73 => (x,y,z) = (1,2,4) or (1,4,2) or (2,1,4) or (2,4,1) or (4,1,2) or (4,2,1)

For k= 80=> (x,y,z)= (2,2,4) or (2,4,2) or (4,2,2)

For k = 81 => (x,y,z) = (3,3,3)

For k = 90 => (x,y,z) = (11,-9,-6) or (11,-6,-9) or (-9,11,-6) or (-9,-6,11) or (-6,-9,11) or (-6,11,-9)

k = 99 => (x,y,z) = (4,3,2) or (4,2,3) or (2,3,4) or (2,4,3) or ( 3,2,4 ) or (3,4,2)

(x,y,z) = (5,-3,1) or (5,1,-3) or (-3,5,1) or (-3,1,5) or (1,-3,5) or (1,5,-3)

=> 5^3 + (-3)^3 +1 = 125 -27 +1 = 99 => for k = 99

For K = 92

6^3 + (-5)^3 +1 = 216 -125 +1 = 92

8^3 +(-7)^3

Step-by-step explanation:

4 0
3 years ago
Please choose all irational thx ^_^
lana66690 [7]

Answer:

Here is a note to help you: Most numbers are rational numbers. Here is how you know when a number is rational or not [especially if its a decimal].

Rational:

- Decimals are usually rational. Rational decimals my look like this:

1) 0.25

2) 0.333333333...

3) 0.234234234234234234...

The following above are rational because they either: terminate or repeat. That being said, 1) terminates, and 2) and 3) repeat because the pattern of 2) is just 3's, and the pattern of 3) is 0.234 over and over again.

Irrational:

- Irrational numbers are numbers that don't repeat, and don't terminate. The next examples are irrational:

1) 0.234536718092343...

2) 8.123456789023452574794832468...

3) 1723456.4356784794954233690422...

- They go on forever and ever, and don't have a pattern/terminate like rational numbers.

Now that you've got that in the bag, its time for your answers!

Step-by-step explanation:

A) rational --> It has a pattern, but does not terminate

B) rational --> It terminates

C) irrational --> it does not have a pattern, even if it does terminate

D) rational --> when you solve it, the answer is 2, and 2 is rational

E) irrational --> it does not have a pattern, but does terminate

I hope I helped you! This took forever, but it was worth it! :D

<h2><u>PLEASE MARK BRAINLIEST!</u></h2>

<u></u>

6 0
2 years ago
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