Answer:
false: positive and negative numbers are on two completely opposite sides of a number line, coordinate plane, etc. Just like 4 is different than 5, it is the same with positive and negative numbers
Your answer would be -22 = -18
Ok what am I supposed to answer?
Answer:
71.123 mph ≤ μ ≤ 77.277 mph
Step-by-step explanation:
Taking into account that the speed of all cars traveling on this highway have a normal distribution and we can only know the mean and the standard deviation of the sample, the confidence interval for the mean is calculated as:
≤ μ ≤ 
Where m is the mean of the sample, s is the standard deviation of the sample, n is the size of the sample, μ is the mean speed of all cars, and
is the number for t-student distribution where a/2 is the amount of area in one tail and n-1 are the degrees of freedom.
the mean and the standard deviation of the sample are equal to 74.2 and 5.3083 respectively, the size of the sample is 10, the distribution t- student has 9 degrees of freedom and the value of a is 10%.
So, if we replace m by 74.2, s by 5.3083, n by 10 and
by 1.8331, we get that the 90% confidence interval for the mean speed is:
≤ μ ≤ 
74.2 - 3.077 ≤ μ ≤ 74.2 + 3.077
71.123 ≤ μ ≤ 77.277
The fractions you're given can be simplified down, so you get (12 ÷ 3) 4 hours on Monday, (21 ÷ 3) 7 hours on Tuesday, and (22 ÷ 3) 7 1/3 hours on Wednesday. You can now add these up and get your answer as 18 1/3 hours, or 18.33.
I hope this helps!