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bezimeni [28]
3 years ago
12

Suppose that an automobile manufacturer advertises that its new hybrid car has a mean gas mileage of 50 miles per gallon. You ta

ke a simple random sample of n = 30 hybrid vehicles and test their gas mileage. You find that in this sample, the average is 47 miles per gallon with a standard deviation of 5.5 miles per gallon. Is there enough evidence to support the advertised claim using α = 0.05? What is the null and alternative hypothesis for this problem?
Mathematics
1 answer:
aleksandr82 [10.1K]3 years ago
5 0

Answer:

Step-by-step explanation:

Given that,

H0 : µ = 50

Ha : µ ≠ 50

α = 0.05

x¯ = 47

s = 5.5

To find the score, we will use the formula below,

z =(x¯ − µ)/s/√n

z =47 − 50/5.5/√30

z = −3.0/1.0042

z = -2.988

z ≈ -3

The cumulative area for this z-score is 0.0013.

This is a two-tailed test:

P = 2(0.0013) = 0.0026.

Since P = 0.0026 < 0.05 = α, we make the decision to reject the null hypothesis.

This means that there is not enough statistical evidence to support the advertiser’s claim of an average of 50 miles per gallon.

Also,

The critical value for a two tailed test is zc = 1.96

Since it is observed that

|z| = |-3| = 3> 1.96 = zc

It is then concluded that the null hypothesis is rejected.

Confidence interval

Xˉ ± zc • σ/√n

47 ± 1.96 ×5.5/√30

47 ± 1.96

(45.032, 48.968) gallons

​

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4 0
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Read 2 more answers
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Romashka [77]

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If we divide 12 by 8, we get exactly 1.5.

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You are arguing over a cell phone while trailing an unmarked police car by 25 m; both your car and the police car are traveling
BARSIC [14]

Answer:

  (a) 15 m

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Step-by-step explanation:

We can choose the frame of reference to be the trailing car. We can start counting time from the point the lead car begins deceleration. Then its position (in meters) relative to the trailing car is ...

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(a) Then the distance between cars at t=2 is ...

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__

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At the closure speed of 12 m/s, it will take an additional ...

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_____

<em>Comment on following distance</em>

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