The second answer is right
Answer:
The two sample t-test
Step-by-step explanation:
The appropriate test for thus is the two sample t test which is also known as the independent t test. This tests aims at determined whether there is a statistically significant difference between the means in two unrelated groups which in this context are a random sample with one type of preservative and another sample with another type of preservatives.
With this test, the researcher is able to compare the mean shelf lives of the bananas treated with the two different preservatives... The null hypothesis equalises the two means of the sample while the alternative does otherwise.
Answer:
-5 and -5.5;
-12.5 and 2
Step-by-step explanation:
Two negative addends, can be added together to give -10.5.
For example:
(-5) + (-5.5) = -5 - 5.5 = -10.5
Also, it is possible for one of the addends to be negative while the other is positive, and their sum will give us -10.5.
For example:
The sum of -12.5 and 2 will give us -10.5.
We are adding a positive and a negative number here. As usual, we will subtract the smaller number from the bigger number, while the result will carry the sign of the bigger number, which in this case is negative sign.
Thus:
(-12.5) + (2) = -10.5
Answer:

Step-by-step explanation:
In order to write the series using the summation notation, first we need to find the nth term of the sequence formed. The sequence generated by the series is an arithmetic sequence as shown;
4, 8, 12, 16, 20...80
The nth term of an arithmetic sequence is expressed as Tn = a +(n-1)d
a is the first term = 4
d is the common difference = 21-8 = 8-4 = 4
n is the number of terms
On substituting, Tn = 4+(n-1)4
Tn = 4+4n-4
Tn = 4n
The nth term of the series is 4n.
Since the last term is 80, L = 4n
80 = 4n
n = 80/4
n = 20
This shows that the total number of terms in the sequence is 20
According to the series given 4 + 8 + 12 + 16 + 20+ . . . + 80
, we are to take the sum of the first 20terms of the sequence. Using summation notation;
4 + 8 + 12 + 16 + 20+ . . . + 80 = 
<span>(-5/6) + c = (-11/12)
c=-11\12+5\6
c=19\12 or 1 7\12</span>