A family is driving 1,036 miles to visit the Blue Ridge Parkway. If they travel at an average of 56 miles per hour, how long wil
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Answer:
We need a sample size of at least 101
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
What sample size is needed to estimate the true average speed to within 2 mph at 99% confidence?
We need a sample of at least n.
n is found when M = 2. So
Rounding up
We need a sample size of at least 101
Answer:
<h2><em><u>Option</u></em><em><u> </u></em><em><u>B</u></em><em><u>:</u></em></h2><h3><em><u>112</u></em><em><u> </u></em><em><u>families</u></em><em><u> </u></em></h3>Step-by-step explanation:
<em><u>Given</u></em><em><u>,</u></em>
No. of families = 75
Out of 75 no. of families had cars = 42
Out of 1, no. of families can have cars
<em><u>Therefore</u></em><em><u>, </u></em>
Out of 200 families, no. of families had cars
= 8 × 14
= 112
<em><u>Hence</u></em><em><u>, </u></em>
<em><u>option</u></em><em><u> </u></em><em><u>B</u></em><em><u> </u></em><em><u>is</u></em><em><u> </u></em><em><u>correct</u></em><em><u> </u></em><em><u>as</u></em><em><u> </u></em><em><u>112</u></em><em><u> </u></em><em><u>families</u></em><em><u> </u></em><em><u>have</u></em><em><u> </u></em><em><u>cars</u></em><em><u> </u></em><em><u>out</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>200</u></em><em><u> </u></em><em><u>families</u></em><em><u> </u></em><em><u>(</u></em><em><u>Ans</u></em><em><u>)</u></em>