The correct answer for the question that is being presented above is this one: "<span>A) The temperature only adds 14 to the damage index." </span>Sven investigates the amount of damage to the head gaskets on the trucks in his fleet and find that the damage index depends on the ambient temperature.

7 0

4 years ago

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Data were collected on the amount spent by 64 customers for lunch at a major Houston restaurant. These data are contained in the

galina1969 [7]

Answer:

a. The margin of error is 2.29.

b. 19.23 to 23.81

Step-by-step explanation:

The sample size is n=64.

We start by calculating the sample mean and standard deviation with the following formulas:

$M=\dfrac{1}{n}\sum_{i=1}^n\,x_i\\\\\\s=\sqrt{\dfrac{1}{n-1}\sum_{i=1}^n\,(x_i-M)^2}$

The sample mean is M=21.52.

The sample standard deviation is s=6.89.

We have to calculate a 99% confidence interval for the mean.

The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.

When σ is not known, s divided by the square root of N is used as an estimate of σM:

$s_M=\dfrac{s}{\sqrt{N}}=\dfrac{6.89}{\sqrt{64}}=\dfrac{6.89}{8}=0.861$

The degrees of freedom for this sample size are:

$df=n-1=64-1=63$

The t-value for a 99% confidence interval and 63 degrees of freedom is t=2.656.

The margin of error (MOE) can be calculated as:

$MOE=t\cdot s_M=2.656 \cdot 0.861=2.29$

Then, the lower and upper bounds of the confidence interval are:

LL=M-t \cdot s_M = 21.52-2.29=19.23\\\\UL=M+t \cdot s_M = 21.52+2.29=23.81

The 99% confidence interval for the mean is (19.23, 23.81).

5 0

3 years ago

10y + 12 - 7y - 8 - 3y = ?

Misha Larkins [42]

Answer:

The answer is 4 :)

Step-by-step explanation:

6 0

3 years ago