Answer:
The t distribution is used, because we have the standard deviation for the sample.
Step-by-step explanation:
When to use the z or the t distribution?
When we have the standard deviation for the population, we use the z distribution.
When we have the standard deviation for the sample, we use the t distribution.
In this question:
We have the standard deviation for the sample, which means that the t distribution is used.
Answer:
How may pandas were born in 2006
Step-by-step explanation:
There would be 14 female and 7 male, so the total number of students is 21.
Answer:

Step-by-step explanation:
Given
The attached graph
Required
Determine the range of the graph
First, we list out the coordinate of each point on the graph:
The points are:

A function has the form: (x,y)
Where
y = range:
From the coordinate points above,

Order from least to greatest"

Hence, the range are: 
Look at the first line: y = (3/5)x - 3. What happens if you multiply each term by 5, to eliminate the fraction?
5y = 3x - 3
Compare this to the second equation,
5y - 3x = -10, or 5y = 3x - 10.
The coefficients of x and y (as 3 and 5 here) determine the slope of a straight line. Since 5y = 3x is present in both equations, the two lines MUST be parallel.
y = 4
4y = 6 => y = 6/4
y+4 and y =3/2 are both horizontal lines. Since they are horiz., they are parallel.