Answer: The margin of error = 3.71, confidence interval = (354.04, 361.46) and it means that mean cost is lies within the confidence interval.

Step-by-step explanation:

Since we have given that

Sample size = 400

Mean = $357.75

Standard deviation = $37.89

At 95% confidence level, z = 1.96

We first find the margin of error.

Margin of error is given by

$z\times \dfrac{\sigma}{\sqrt{n}}\\\\=1.96\times \dfrac{37.89}{\sqrt{400}}\\\\=3.71$

95% confidence interval would be

$\bar{x}\pm \text{margin of error}\\\\=357.75\pm 3.71\\\\=(357.75-3.71,357.75+3.71)\\\\=(354.04,361.46)$

Hence, the margin of error = 3.71, confidence interval = (354.04, 361.46) and it means that mean cost is lies within the confidence interval.

7 0

3 years ago

Which sequences of transformations confirm the congruence of shape II and shape I?

mylen [45]

Answer:

1. When we reflect the shape I along X axis it will take the shape I in first quadrant, and then if we rotate the shape I by 90° clockwise, it will take the shape again in second quadrant . So we are not getting shape II. This Option is Incorrect.

2. Second Option is correct , because by reflecting the shape I across X axis and then by 90° counterclockwise rotation will take the Shape I in second quadrant ,where we are getting shape II.

3. a reflection of shape I across the y-axis followed by a 90° counterclockwise rotation about the origin takes the shape I in fourth Quadrant. →→ Incorrect option.

4. This option is correct, because after reflecting the shape through Y axis ,and then rotating the shape through an angle of 90° in clockwise direction takes it in second quadrant.

5. A reflection of shape I across the x-axis followed by a 180° rotation about the origin takes the shape I in third quadrant.→→Incorrect option

6 0

3 years ago

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