Multiplicative inverse of 21/49
1 answer:
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Answer:
61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.
Step-by-step explanation:
Given : We want 95% confidence that the sample mean is within 3 minutes of the population mean, and the population standard deviation is known to be 12 minutes.
To find : How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters?
Solution :
At 95% confidence the z-value is z=1.96
The sample mean is within 3 minutes of the population mean i.e. margin of error is E=3 minutes
The population standard deviation is s=12 minutes
n is the number of sample
The formula of margin of error is given by,
Substitute the value in the formula,
Squaring both side,
Therefore, 61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.
Answer:
The correct answer is 61.08 foot.
Step-by-step explanation:
Length of the string of the kite, Mr. Black is flying is 65 foot. Thus the length between the kite and Mr. Black is given by 65 foot.
Angle of elevation is 70°.
We need to calculate the height of the kite above Mr. Black's head. The height is given by finding the sine of the angle of elevation.
Let the height be x foot.
Thus sin 70° =
⇒ x = sin 70° × 65
⇒ x = 61.08
Thus the height of the kite above Mr. Black head is 61.08 foot.