A least squares regression line: a. may be used to predict a value of y if the corresponding x value is given b. implies a cause
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Answer:
We need at least 243 stores.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error of the interval is:
For this problem, we have that:
95% confidence level
So , z is the value of Z that has a pvalue of
, so
.
Determine the number of stores that must be sampled in order to estimate the true proportion to within 0.04 with 95% confidence using the large-sample method.
We need at least n stores.
n is found when M = 0.04. So
Rounding up
We need at least 243 stores.
The time taken by the first and the second train is 1 hour 40 minutes and 1 hour 25 minutes. Then the time when the second train at Niles junction is 5:55 p.m.
<h3>What is speed?</h3>The distance covered by the particle or the body in an hour is called speed. It is a scalar quantity. It is the ratio of distance to time.
We know that the speed formula
A train leaves Thorn junction at 1:25 p.m. and arrives in Niles at 3:05 p.m. the train makes two stops along the route for a total of 15 minutes.
A second train leaves Thorn junction at 4:30 p.m. and heads to Niles.
This train does not make any stops.
Let the speed of both trains be equal.
Then the time taken by the first train will be
t₁ = 3:05 p.m. - 1:25 p.m.
t₁ = 1 hour 40 minutes
Then the time taken by the second train will be
t₂ = 1:40 - 00:15
t₂ = 1:25 = 1 hour 25 minutes
The time when the second train is at Niles junction will be
→ 4:30 p.m. + 1:25
→ 5:55 p.m.
More about the speed link is given below.
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