Answer:
The degrees of freedom are given by:

The p value for this case would be given by:
Since the p value is higher than the significance level we have enough evidence to FAIL to reject the null hypothesis and we can conclude that the true deviation is not ignificantly lower than 5 minutes
Step-by-step explanation:
Information given
represent the sample size
represent the confidence level
represent the sample variance
represent the value that we want to verify
System of hypothesis
We want to test if the true deviation for this case is lesss than 5minutes, so the system of hypothesis would be:
Null Hypothesis:
Alternative hypothesis:
The statistic is given by:
And replacing we got:
The degrees of freedom are given by:

The p value for this case would be given by:
Since the p value is higher than the significance level we have enough evidence to FAIL to reject the null hypothesis and we can conclude that the true deviation is not ignificantly lower than 5 minutes
40/2=20
Therefore he can cover 20 miles in 1 hour
Hope this helps!
Answer:
Just Between Friends
The percentage of consignors who receive a check for more than $370 is:
= 16%.
Step-by-step explanation:
Mean of consignor check, μ = $480
Standard deviation, σ = $110
Value of check received, x > $370
Solution: find the z-score to determine the percentage of consignors who receive a check for more than $370:
z = (x-μ)/σ
z= ($370 - $480)/$110
z = -$110/$110
z = -1.00
Percentage of consignors who receive a check for more than $370
= 0.15866
= 0.16
= 16%
Answer:
See proof below
Step-by-step explanation:
Let
. If w=-z, then r=0 and r is real. Suppose that w≠-z, that is, r≠0.
Remember this useful identity: if x is a complex number then
where
is the conjugate of x.
Now, using the properties of the conjugate (the conjugate of the sum(product) of two numbers is the sum(product) of the conjugates):

=
Thus
. From this,
. A complex number is real if and only if it is equal to its conjugate, therefore r is real.
Step-by-step explanation:
4x2+8x−3=0
For this equation: a=4, b=8, c=-3
4x2+8x+−3=0
Step 1: Use quadratic formula with a=4, b=8, c=-3.
x=
−b±√b2−4ac
2a
x= −(8)±√(8)2−4(4)(−3)
2(4)
x= −8±√112
8 x=−1+
1 2 √7 or x=−1+
−1 2 √7
Answer: x=−1+
1 2√7 or x=−1+
−1 2 √7