4y - 18 = 20 Y= PLEASE HELP!!!!!!!
2 answers:
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<h2><u>Answer:</u></h2>
Pi = 3.14
Diameter (d) = 86 cm
•°• Radius (r) = 86 ÷ 2 = 43 cm (radius is 1/2 of diameter)
Area of the circle = ?
Formula,
Substitute the value of 'r' & pi in the formula.
⎆ The area of the circle is about <u>5</u><u>8</u><u>0</u><u>5</u><u>.</u><u>8</u><u>6</u><u> </u>cm² (approx.)
<h3>Answer: 8.323 (approximate)</h3>
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Explanation:
s = 32 = sample standard deviation
n = 40 = sample size
Despite not knowing the population standard deviation (sigma), we can still use the Z distribution because n > 30. When n is this large, the student T distribution is approximately the same (more or less) compared to the standard Z distribution. The Z distribution is nicer to work with.
At 90% confidence, the z critical value is roughly z = 1.645. This can be found using either a Z table or a calculator.
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We have these values:
- z = 1.645 (approximate)
- s = 32
- n = 40
Plug these values into the margin of error formula.
The margin of error is roughly 8.323
I rounded to 3 decimal places because z = 1.645 is rounded to 3 decimal places. If your teacher wants some other level of precision, then be sure to follow those instructions.