Help fast worth 10points
1 answer:
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Average speed =
Ishan's Speed uphill = 10mph
Time taken = 18 minutes = 18/60 = 3/10 hours
Now distance = rate × time
Distance traveled by Ishaan up hill = 10 × 3/10 = 3 miles
Now returning back home
Distance = 3 miles
Rate = 30 mph
So time taken = distance/ rate = 3/30= 1/10 hours = 1/10 ×60 = 6 minutes.
Now total distance traveled = 3 + 3 = 6 miles
Total time taken = 18 + 6 = 24 minutes = 24/60 = 2/5 hours
Average speed
=
= 15 mph
Ishaan's average speed for the entire trip from home to the gift store and back is 15mph
Answer:
C. Decreases the margin of error and hence increases the precision
Step-by-step explanation:
If we select a sample by Simple Random Sampling in a population of “infinite” size (a population so large that we do not know its size exactly), then the margin of error is given by
where
<em>Z = The Z-score corresponding to the confidence level </em>
<em>S = The estimated standard deviation of the population </em>
<em>n = the size of the sample. </em>
As we can see, since n is in the denominator of the fraction and the numerator is kept constant, the larger the sample size the smaller the margin of error, so the correct choice is:
C. Decreases the margin of error and hence increases the precision