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Assoli18 [71]
3 years ago
6

A brick staircase has 20 steps. The bottom step up has 80 bricks, the next step up has 78 bricks, the next step up has 76 bricks

, and so on.
What explicit rule best represents the sequence 80,78,76,...?

Mathematics
2 answers:
rjkz [21]3 years ago
7 0

Answer:

The explicit rule best represents the sequence 80,78,76,... is an = 78 + 2n

Step-by-step explanation:

Given Parameters.

Number of steps = 20

The bottom step = 80 bricks

The next step = 78 bricks,

The next step = 76 bricks,

Required:

What explicit rule best represents the sequence 80,78,76,...?

The topic in this question is arithmetic progression.

The nth term of a progression is solved using the formula

Tn = a + (n - 1)d

Where Tn represent the nth term

a = first term

n = number of terms

d = common difference

Comparing the above to the parameters in the question

a = first step = 80 bricks

n = number of steps =

d = common difference between 2 steps = 80 - 78 or 78 - 76

d = 2

Tn represents an

By Substituton, we have

an = 80 + (n - 1)2.

Open bracket

an = 80 + 2n - 2

Collect like terms

an = 80 - 2 + 2n

an = 78 + 2n

Hence, the explicit rule best represents the sequence 80,78,76,... is an = 78 + 2n

lesya [120]3 years ago
6 0

Answer:

aₙ = 82 - 2n

Step-by-step explanation:

aₙ = 82 - 2n

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The calculated chi -square  value =5.7356 Is less than12.01 at 0.1level of significance .

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Step-by-step explanation:

<u>Step:-(1)</u>

Given data 28 25 29 25 32 36 27 24

Sample size 'n' = 8

mean of the sample (x⁻) = ∑x /n = \frac{28+ 25+ 29 +25 +32 +36 + 27 + 24}{8}

mean of the sample (x⁻) =  28.25

x                           x- x⁻                         (x-x⁻ )²

28              28 - 28.25  = -0.25       0.0625    

25             25 -28.25   = -3.25       10.56

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24            24-28.25    = -4.25      18.06

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The sample standard deviation

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   By using χ² distribution

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By above test can be applied only if the population from which sample is drawn normal.

Given data For the past 5 years, a driver has tracked the gas mileage of his car and found that the variance from fill-up to fill-up was σ2 = 23 mpg^2.

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Null hypothesis :H₀:σ² = 23

Alternative hypothesis :H₁:≠23

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The null hypothesis is accepted.

<u>Conclusion</u>:-

The null hypothesis is accepted.

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