Answer: t = 1.9287
Step-by-step explanation:
Let be the average number of pages should be sent by 2-day mail instead.
As per given we have,
Sample mean :
Sample standard deviation : s=3.81
sample size : n= 24
Since , the sample size is less than 30 and populations standard deviation is unknown , so we use t-test.
The test statistic for population mean :-
Hence, the test statistics : t = 1.9287
Answer:
x = - 4 ± 2
Step-by-step explanation:
Given
f(x) = x² + 8x + 4
To find the zeros let f(x) = 0, that is
x² + 8x + 4 = 0 ( subtract 4 from both sides )
x² + 8x = - 4
To solve using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(4)x + 16 = - 4 + 16
(x + 4)² = 12 ( take the square root of both sides )
x + 4 = ± = ± 2
( subtract 4 from both sides )
x = - 4 ± 2
Thus the zeros are
x = - 4 - 2 and x = - 4 + 2