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3 years ago

Multiple choice (you can choose more than one)

Mathematics

1 answer:

sertanlavr [38]3 years ago

4 0

Answer:

A and D

Step-by-step explanation:

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The manager of a fleet of automobiles is testing two brands of radial tires and assigns one tire of each brand at random to the

Feliz [49]

Answer:

a) σ = 4933,64

b) CI 99% = ( - 5746 ; 7194 )

c) No difference in brands

Step-by-step explanation:

Brand 1:

n₁ = 8

x₁ = 38222

s₁ = 4974

Brand 2:

n₂ = 8

x₂ = 37498

s₂ = 4893

As n₁ = n₂ = 8 Small sample we work with t -student table

degree of freedom df = n₁ + n₂ - 2 df = 8 +8 -2 df = 14

CI = 99 % CI = 0,99

From t-student table we find t(c) = 2,624

CI = ( x₁ - x₂ ) ± t(c) * √σ²/n₁ + σ²/n₂

σ² = [( n₁ - 1 ) *s₁² + ( n₂ - 1 ) * s₂² ] / n₁ +n₂ -2

σ² = 7* (4974)² + 7*( 4893)² / 14

σ² = 24340783 σ = 4933,64

√ σ²/n₁ + σ²/n₂ = √ 24340783/8 + 24340783/8

√ σ²/n₁ + σ²/n₂ = 2466

CI 99% = ( x₁ - x₂ ) ± 2,624* 2466

CI 99% = 724 ± 6470

CI 99% = ( - 5746 ; 7194 )

As we can see CI 99% contains 0 and that means that there is not statistical difference between mean life of the two groups

3 0

3 years ago

THE SUM OF THE DIGITS OF A CERTAIN TWO-DIGIT NUMBER IS 13. REVERSING ITS DIGITS INCREASED THE NUMBER BY 9. WHAT IS THE NUMBER?

KonstantinChe [14]

Answer:

Step-by-step explanation:

Adding 6 and 7 together equate to 13. You then switch the digits of 67 to 76 and the number is increased by 9.

5 0

3 years ago

What is the exact value of sin pi/12

Step2247 [10]

Answer:

hey,see the attachment

excuse for poor quality chalk

it isnt bright

4 0

3 years ago

2x - (3x + 6) Please help me with this equation guys!!!

katen-ka-za [31]

1. 2x - (3x + 6).....negative before parentheses makes everything inside parentheses opposite
2. 2x - 3x - 6....2x - 3x = -1x
3. -1x - 6

Answer:
-1x - 6

4 0

3 years ago

Tammy has scored 82, 78, and 93 on her previous three tests. What score does she need on her next test so that her average (mean

Lyrx [107]

Answer:

She needs a grade of 71 on her next text.

Step-by-step explanation:

Mean of a data-set:

The mean of a data-set is the sum of all values in the data-set divided by the number of values.

Tammy has scored 82, 78, and 93 on her previous three tests.

Thus, her grades are 82, 78, 93 and x, in which x is her grade in the fourth test.

There are 4 tests.

What score does she need on her next test so that her average (mean) is 81?

We have to find x when the mean is 81. So

$\frac{82 + 78 + 93 + x}{4} = 81$

$253 + x = 324$

$x = 324 - 253$

$x = 71$

She needs a grade of 71 on her next text.

5 0

3 years ago